Well now that I have decided to build a M4A3 Sherman I am wondering how to weather it.
I havent weathered anything before so I need something simple to do to make it look a little worn.
I would like to do a weathering of a tank used in France.
So anyone got some tips about how do go about this?

Hey Dale, weathering is a fun step and can be very creative, there is no correct way to go about it. Some people stick to layers of paint simulating dust and light dirt whereas others pile on loads of plaster covered in static grass and pigments to replicate mud and grass clods.
Have a look around at period pics of tanks to see the level you wish to take it, less is truly more with this step.
A basic amount would be a sludge wash and some dust colored paint sprayed around the running gear/hull sides to portray dust build up.
There are countless articles around the web, Mig does some good ones here
rarities world

And Steve Zaloga has quite a few excellent books on building shermans and stuarts including advice on weathering.

whew. hope that helps.
Cheers, Stoney.

First, are you airbrush savvy? If so, use a rust pigment and give the road wheels and suspension a light coat. Spread some fine or medium grit putty over the inside of the tracks. Add a few small dabs on the suspension and roadwheels. Spread some of the putty under the transmission cover. After the putty dries, paint it with 'French Earth'. Take a soft-lead pencil and run it over hard edges. I've heard a silver colored pencil works as well. Add a few paint chips by stipling on dark grey. You can add rain streaks with oils, but I have no experience in this. After you have done that, apply a light buff coat(80% thinner) over the entire model.

I dont own a airbrush.
I am really looking for a simple technique that is very newbie frindly.

Dale,
I would say that you have chosen the perfect subject! A Sherman that was new to France would not have seen very much in the way of weathering if it has just arrived. Google Images can provide you with some ref. pics.
The first thing to do is decide ahead of time exactly what you want the desired outcome or look to be. It is hard to move forward with out a destination in mind! DO NOT let your paint give you an outcome......you are in control.....you tell the paint what to do!
The first thing you can do to give some light weathering to your project is to give a panel line wash.
First, this works best over a satin or gloss surface. This allows the heavily thinned ( 85% - 90% ) paints to flow over the painted surface. This also allows you to clean up around the edges of panel lines if you and up with your wash on a neighboring surface unintentionally.
This forum is full of helpfull folks. If you like, you can post up pics of your progress. Myself and others will be able to help you get the results you are looking for if we can see where your project is currently.

I suggest you invest in one of Steven Zaloga's modeling books published by Osprey. He walks you through a very simple and highly effective approach to painting and weathering, and I find his techniques yield more realistic results than the European approaches currently in vogue. If you search on Missing-Lynx, you'll find some of his builds, many of them for "MIlitary Modelling Magazine" in the UK, and you can judge for yourself.
In magazines and on the Internet, I see a lot of model finishes that look "cool," with preshading, postshading, filters, and scores of little paint chips, but they don't look like anything I've ever seen in the real world. Models should be based on real objects, not other models. Each of these techniques can be useful sometimes, but not all of them, every time--it's like nobody knows when to stop. But Zaloga's models just look convincing to me.
His book, "Modeling US Armor of World War 2 (Modelling Masterclass)," is devoted to US vehicles in general.
He covers much of the same material in his books on the building and detailing of Shermans specifically, "Modelling the US Army M4 (76mm) Sherman Medium Tank (Osprey Modelling)," and "Modelling the US Army M4 (75mm) Sherman Medium Tank (Osprey Modelling)."
These Osprey titles are all available discounted from Amazon.com.

Thanks for the help everyone.
With so many different spray can OD colors to chose from witch one do you prefer and why?

Do a search for "Olive Drab" and you'll get plenty of info. Tamiya Olive Drab is a good match for fresh No. 9 Olive Drab from WW2, but the color is too dark and saturated for a model (colors appear lighter and less saturated when viewed outdoors from a distance, so most model builders lighten the base color, so-called "scale effect"). The Tamiya color can be lightened with perhaps about 20% German Dark Yellow (an ochre color), but you'll need to airbrush the mix.
The other makers' Olive Drab paints (such as Testors Model Master) are mostly matched to the wrong FS-595a color chip, one that matches a warmer, lighter Olive Drab formulated for helicopters during the Vietnam War (FS-34087). However, this color is about light enough to depict "scale" No. 9 Olive Drab, though it's a little too vivid in color (a dusty weathering can reduce this, though).

Well it looks like the Tamiya is really my best choice then.

hi dale check out scalemodel medic on you tube he does some top little videos on weathering you might pick up a few bits and bobs

First off, what materials do you have on hand? what paints (brands too)

Hi Dale, did you say you dont have an airbrush,dont use Tamyia paint then its only good for spraying if you can can get them try Vallejo excellent for hand brushing good colour range too,I wouldnt worry to much about "correct olive drab" as most of the French campaign was in the summer so a dusty finish would negate the shade of OD .good luck with the build.

Well the only paints I have on hand are Model Master spray cans but they are automobile colors.
I am going to pick up a spray can of the Tamiya OD at the same time I pick up the Sherman. That probably wont be untill next Saturday though.
Thanks again for everyones help.