Tried the alternative solution on this website:

http://thenokiablog.com/2009/04/08/h...transcription/

But it doesnt work. Any number that I put in as my Forwarding number was considered an "Invalid Number".

I tried all the following formats:
+1GVnumber
+GVnumber
1GVnumber
GVnumber

None worked. Any help getting google voice to work with my n900 would be great.