In addition to maxing out your RAM (as suggested by Rick Deckard) I urge you, in no uncertain terms, to upgrade your OS to no less than 10.3.9, the final incarnation of Panther
(Edit: It was a*major* improvement over Jaguar.); your TiBook will also support OS X 10.4.11, the final incarnation of Tiger, but I'm not certain how well that will run on a 550MHz machine. (In all likelihood, others will advise you.)
Note that Panther comes on CDs, but Tiger, in its inexpensive form, is on DVDs, so you'll need a DVD capable optical drive to install it. (CDs are available, but they tend to be prohibitively expensive.)
Note also that if you buy either OS you want to buy generic, i.e. *black label*, retail install discs; discs with grey labels are machine specific, and unless you are lucky enough to find a set that originally shipped with your *precise* model of Mac you will be throwing your money away.
Next, I suggest that you free up as much space on your HD as you can by off-loading (to an external HD if necessary) stuff, such as music, that takes up a lot of space; together with maxing out your RAM
(Edit: Note that Photoshop is a notorious RAM hog!), this will enable your Mac to run better.
And in closing, I'll mention that a new Mac does not have to be all that expensive; a bottom of the line
MacBook (Click on Tech Specs to be amazed!) costs only $999 and can be had for less if you buy a refurb *directly from Apple*. (I'd be wary of anything for sale on eBay...too many problems with such stuff have been posted.)
A Mac Mini can be had for only $599, but you'll need a monitor and keyboard.
Hope this helps.
