Google Voice
Used by 6 peopleen.wikipedia.org ↗

“Sometimes I'm not at my computer, though, and for that I can use my phone to record calls with Google Voice; you just hit a button and it announces the call is being recorded, and then an MP3 gets dropped in your Google Voice account after the call ends.”
Alissa Wilkinson Interview, Staff reporter, film critic (Vox) · via Uses This 
“That said, every iPhone user I know thinks I'm a magician because I can gChat with them while I walk around and still can't entirely comprehend how Google Voice works like it does on this phone, so suck on that.”
Daniel Sinker Interview, Director, Knight-Mozilla OpenNews · via Uses This 
“As for apps, I love the integration of Google Voice, Docs, Gmail and Contacts with the Nexus One.”
Alexandra Klasinski Interview, Photographer, designer · via Uses This