The only way to get that is by letting someone other than your carrier handle the voicemail. For example, grandcentral.com has visual voicemail via their mobile web interface (free). However, you would have to setup your voicemail to be handled by them instead of with your carrier. It's possible as I've read threads where others have used 3rd party voicemail providers. I have not done this myself, so I can't explain how its done.
Check out this wiki for other options -
http://en.wikipedia.org/wiki/Visual_voicemail