Have you tried Google Voice?

Google has launched a FREE Unified Communication solution.
Use 1 free phone number to access all your phones.

You can create your own Google number and get all these features:

• One Number - A single phone number that rings up to 6 other phone numbers
• Screen Callers - listen to hear who is calling before you pick up
• Free SMS - Send, receive & store text messages online
• Block Calls - send unwanted calls directly to voicemail
• Record Calls - record your phone calls and store them online
• Conference Calls - create a conference call with several people on a single call

Google Voice is currently available by invite only. Click Here to request an invitation.