Cydia is an application manager that you can use on your jailbroken iPod. I’m a big fan of it because it has enabled me to SSH as well as VNC to the iPod — and that’s just the beginning!
Anyway, I was finding installing Cydia-based applications on iPod a bit cumbersome — it would take a bit long. Cyder is an great application which thus came to the rescue! Now I can download apps (plus dependencies) on the PC, and then transfer them to the iPod. (Also helpful when you do not have a WiFi.)
Another cool utility that I came across today is iPhone browser through which (and as the name suggests :P) one can browse the iPhone/iPod file system. It’s quite useful if you don’t want to FTP (over SSH) to your iPhone/iPod to transfer files.