I recently purchased a midi controller and i really like using it with reason 2.5 my question: is it possible to link the two programs together so when i record the instructions in pro tools it uses the reason soundbanks???

not exactly... you can use Rewire depending on which version of PTLE you are using and basically have Reason send its audio to tracks in PTLE but I am not so sure about using midi in PTLE to control Reason... you may have to do all midi work in Reason in its sequencer and then send the the audio output into PTLE. Reason will not work as a soft synth plugin would in RTAS I don't think but others with more experience may be able to help with this more.

Open PT and then boot Reason. Once you have Reason open and Rewired to PT (If you don't know how to do this check out Propellerheadz site), the Reason modules you have loaded will show up in your PT MIDI tracks as output options. This won't use the soundbanks from Reason as a soft synth, but you can Sequence in PT and then port that over to Reason. I think this is what you're asking, but if you need clarification let me know.

Yeah I used the rewire function and it works fine, took a bit of set up with the Pro tools busses to get playback when im recording but its all good now thnx guys