Not sure who has M1A1s there now. 4th ID is currently in Iraq and they have M1A2s and M1A2 SEPs, not M1A1s. Do a google search for M1A1 or Abrams in Iraq and you can find lots of pics. Also, check out the 4 ID web page for a listing of thier units. Any unit listed as a Combined Arms Bn (CAB), Armour Bn, or Armoured Reconaissance Squadron (ARS) will have Abrams.
USMC tank Bns use M1A1s, not sure which USMC tank Bn is there now though.
If you are just looking for recent markings for an Abrams in OIF, try the Echelon "US Army's OPERATION IRAQI FREEDOM M1A1HA (Heavy Common) ABRAMS (Part 4)" decal sheet.
Here is a review of it by Vodnik. It has markings and color info for 7 different M1A1s from 3ID and 1AD in Iraq. Their other OIF Abrams sheets are great too, they are for 3ID and USMC tanks.