Texting or messaging app that can also be used online?

[Phyllon]

Is there a texting or instant messaging app, like Kik, Whatsapp, etc, that can also be used online / on a regular PC?

I mean besides using it as a mobile app on my phone, I'd also like to be able to send and receive messages through a website, so it can also be used from a Windows desktop PC for example.

 

[DragonSlayer95]

Mysms

Sent From My HTC Evo 3D Using TapaTalk 2

 

[Tre Lawrence]

Google Voice. MMS is currently handicapped though.