a recent task I had to do involved getting a bunch of old versions of applications. The search for these brought me to a website www.oldapps.com. I first came across this website from watching Tekzilla. (good video podcast for tech fans, and the hosts are great!).
The website hosts a lot of popular applications, and every version of those software that have been publicly available. Most of the times, these software are no longer found on their main website, and even hard to find on the P2P network. Fret not as this site has it!
So, if there are any vintage versions of Winamp that you like, but lost due to a system rebuild. You can hop over to Old Apps and download that favorite version you like.