Hard drive space

[Jennifer Thomas]

Hi,
  I have a year 2000 model iMac (version = 32.1) 350 Mhz, Power PC G3 
using
Mac OSX 10.2.8.  I do not have firewire.

My capacity hard drive space is 6.99 GB, but I'm down to 555.9 MB

First of all, I've gotten rid of applications I'm not using and any 
other large files.

The only large files I have left are in iTunes and iPhoto.  Are there 
any duplicates that
these apps store that I could delete?

Also, how large a hard drive can I install in my computer?

Any other suggestions?

Thanks!

Jennifer