Here are some of the features of Google Voice-
All below are free-
long distance within the US
text messaging
voice mail
voice mail emailed in speech to text translation
call recording
4-way conference calls
many, many more features
https://services.google.com/fb/forms/googlevoiceinvite/
Watch this short video about Google Voice
For a nice step-by-step instructional guide to Google Voice see this page
A Guide To Google Voice – 404 Tech Support