you can do it in any program.
you need "Mouse Keyboard" and "Midi Ox".
mouse keyboard assigns your computer keyboard to certain notes, and midi ox is a virtual midi cable, and the combination of these two will let you play your keyboard in any program that supports midi controllers (any production utility like reason, FL etc)
do some research before you come here expecting easy answers. its not hard to find... go to bome.com for tutorials.
http://bome.com/midi/keyboard/help/rsn3_tut.php
"using Bome's Mouse Keyboard with Propellerhead's Reason 3"
but this is no where as pleasant as having a dedicated midi keyboard. if you sucked at making music with the mouse, you will still suck now.
get a keyboard for the real feeling, its the only way really nice beats beats will come to you.