Making Fun Music Easily with Microsoft Songsmith
Microsoft have created a neat new software package for creating music. It works cleverly by matching music to your vocals! All you need to do is sing (or try :)) into the microphone and Songsmith will do some magic in the background and add music to it. Its great fun for creating jingles or even lullabies!
http://research.microsoft.com/en-us/um/redmond/projects/songsmith/index.html
Its free for the first 6 hours of use and then £25 for a full copy.