Here's GoreBastard's response to one of my reviews, I thought it was pretty helpfull:
"Firstly I use a drum program called Acoustica Beatcraft which you can get from www.acoustica.com. With this program, you can make the drum beat for an entire song, then when you've finished it you convert it into whatever type of file you need it to be, I usually convert it to a WAV file.
Then there's a kick ass piece of hardware and software that I use called a Line 6 Guitar Port. This plugs your guitar straight into your computer, and it has hundreds of different amp models/sounds/effects etc... You can get a really good guitar sound out of it if you play around with it.
Then, I use a recording program called Cubase. With this, you can load up your drum part onto one of the empty tracks, then record along to the drums with the Line 6 Guitar Port running on a seperate track. Cubase has got a bunch of plugins such as echo's, reverbs, and a bunch of other good shit that you can use to add to your guitar or drum sounds. Once you've made your song, the best thing to do is to convert it into a WAV, then get a seperate program to convert that WAV into an MP3 which will fit Newgrounds standards. WAV to MP3 converters can be found pretty cheap, or even free if you search for them on google."
You can also use different (including free) programs to achieve similar results.