that's exactly what i'm trying to set up and hence my question. but i don't want to change my phone number from Sprint to my GV number.
so is it possible and how do i do this???
Sure, you can use Google Voice as a voicemail replacement without switching your phone number. Basically, unanswered and ignored calls will be forwarded to Google instead of Sprint. You can completely forget you have a different number with google voice, if you want.
1) Make sure you have google voice installed on your phone, then go to
www.google.com/voice and login with your account (or set one up if you don't have one).
2) Go to your google voice settings page where you will see your forwarding phones. Add your cell phone if you haven't already.
3) You'll see an option to activate google voicemail on your phone. Select that option, and it will prompt you to set up a conditional call forward on your phone. It will tell you what to do.
Once you've done that, any calls you get to your cell phone (not google voice, but your actual cell phone) that you ignore or miss will go to google instead. You can view those voicemails in the google voice app just like you can with the sprint visual voicemail apps.
EDIT: I forgot one small thing. On the phone to go menu->settings->call and change the Voicemail service to google voice.