What are those 'mini extensions' called?

You know the ones you can put under or over your mini in order to add USB ports and such.

If you know what I'm talking:

1. What are they called?
2. How much do they usually go for?
3. What are the best brands?
4. How do these things work by the way? USB? Firewire?

I know i can rely on you guys for a good answer.
Thanx guys.

trpnmonkey41 said:

http://www.123macmini.com/accessories/guide/hubs.html

Click to expand...

that sort of helps. thanks.

I like them expecially lacies.

They sell them at CompUSA if you have one of those around.

Do those mini hubs on 123macmini.com have powered USB ports? I tried plugging my iPod into my keyboard last night and no power!

If those external harddrive's/hubs are powered then that would be my ultimate solution!.

Any help would be greatly appreciated, and sorry to Hi-jack the thread.