If you can take the cover off, you can take the plates out!
I'd recommend a Haynes manual at this point (order from Amazon
if you must) as that has the complete guide to taking the plates out and putting them back in again.
As for checking, again the Haynes manual will give specifics (plate thickness / pack thickness) but as long as there is some meat on the fibre plates left then they should be fine!
It's not a difficult job - once the cover is off it's only 6 bolts to remove the springs and caps, then the plates come out. Clean them up (a tin of clutch/brake cleaner here is good, but a dry rag is fine) and then get all the dust out of the basket and the pressure plate too. You may want to regrease the bearing on the pressure plate as well - all that dry dust tends to knacker it. Then reassemble and you're done.
[Edited on 26-7-2005 by antonye]