if you have only purchased music from the iTunes Store on your iPods, you can get them back into iTunes directly.
File >> Transfer purchases from iPod
Or if this was imported music from CDs, you cannot drag them back into iTunes. There are third party tools. For Mac you have them for free, but for Windows they want to cash money... unfair, but thats life.
However, there are trial versions. Those are applications that work only for a few days for free, then you need to decide if you want to pay or not. If not, the application turns useless. BUT within those free trial-days you should be able to copy your songs back to your hard drive as MP3-files. Just check www.download.com and search for "iPod". Maybe you also find a free application... who knows.
Good luck!
