Recording 2 input devices at the same time?

Can my sound blaster live audigy platinum do 2 recordings at the same time?

Mic & guitar?

What you would have to do (obviously) is plug one in the microphone jack and the other in the Aux IN jack.
I'm fairly certain that the hardware supports multiple track recording, so that leaves the software end.
It looks like you could do this with Audacity - here is a good info page.
Feel free to check manuals/help files/man pages/wikis/etc for the program you want to use to see if it supports it.

What you need is to use the ASIO driver, that will most likely give you 4-6 input sources to choose from.