Just found a DB9 to RJ11 cable on ebay. Hopefully that'll allow me to use my G25 pedals on my Xbox wheel.
I'm just not ready to pull the trigger on a Fanatec GT2 wheel yet...to many mixed reviews. Either the user loves it or hates it. At least this will make swapping things on my rig a lot easier...only have to detach the wheels depending on if I'm feeling GT or Forza.
Yes it is possible. There is a lot of information on the internet about how to convert the pedal's plug.
Google: G25 plug pinout
http://forums.forzamotorsport.net/forums/thread/2975695.aspx