ACID Pro 7 software is a DAW powerhouse that combines full multitrack recording and mixing </acidpro/mixing>, MIDI sequencing </acidpro/midi>, and legendary ACID looping functionality for a seamless music-creation and post-production environment. More creative partner than production tool, ACID Pro 7 software inspires you like nothing else. With its Transparent Technology™ design, ACID Pro 7 software removes typical barriers to the creative workflow so you can effortlessly transform ideas into real results. The 'crack' for the Pro is included in the download.
ACID Xpress is a free, 10-track version of ACID software for music recording, editing and mixing. It's easy to use, even if you've never tried loop-based music creation before. Just pick some loops, paint them into a track and play them back. Any loops you choose work together because ACID Xpress matches the tempo and pitch automatically. When you're ready, publish your song to ACIDplanet.com.
Once you've installed the Acid software, you're going to need some loops to start putting your song together, this will get you started
More free Loops can be found here as well..