Forward away!
See this press release. I used Google Voice voicemail before this went into effect and was charged $0.20 / minute. I used Google Voice voicemail after this went into effect, and I no longer have call forwarding charges.
Keep in mind this is only conditional call forwarding. So, it applies to no answer and busy forwarding. if you set it to forward conditionally, you will still be charged $0.20 / minute.
http://newsreleases.sprint.com/phoen...107&highlight=