+1 to Fenderhutz... built in laptop mics are really built for very basic voice applications, like webchat stuff.
I use a Toneport UX1 and absolutely love it. The included Gearbox software is great... It's easy to use, there are a bunch of pretty usable stompbox models, you can pick amps/cab models (the basic bundle comes with 5 of each for bass, but there's an add on pack with LOTS more), there are 4 mic models which you can "position" closer or further away from the virtual cabinet... on and on.
Not only does it have mic/instrument inputs, it's got line ins as well... with the small mixer I have hooked up to it, I've got a drum machine and keyboard running through it as well.
They're currently $89.99 at Musician's Friend. If you just need ONE input, the Toneport GX would work fine and still comes with Gearbox. (+1 to Fenderhutz again

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http://www.musiciansfriend.com/produ...ace?sku=249700
Highly recommended!
5sg.