My first port of call would be to visit Sonic Spot
and have a look at some software called 'Fruity Loops'. This software has been around for some time now and features many plugins, tutorials etc.
Also have a look at Hitsquad
a brilliant resource for music information and software.
Head over to Propellerheads website
they have some brilliant software, and have a couple of free downloads such as Rebirth 303!!