sleep freeze

[James Patrick Draine]

Dear List,
I finally (after lurking for half a year) got an iBook; 900 MHz, 
CDR-DVD. So far just the stock 128 meg memory, but I've got an order in 
for 512 M more. It works surprising well for such a meager amount of 
memory, but I'd rather not be accessing the HD every time memory is 
needed for an operation.
So, last night I finally experienced the sleep/freeze phenomenon. I had 
been away from the computer for a half hour, tapped on the keyboard to 
wake it back up, but no reaction. The 'puter was warm and the HD (or 
something) seemed to be humming away. I tried the various keystroke 
combos suggested in the "user's guide". Apparently one of them worked 
because it finally quieted down and cooled off. Seems fine since. I've 
read of others' encounters with this problem but having it happen to ME 
is much more troubling.
What's the list's wisdom on this? Ignore it if it doesn't happen often? 
Websites detailing remedies? Buy a "Little iBook Book"? I would if they 
didn't seem Clamshell oriented, or at least the ones on the local 
Barnes & Noble's shelves are.
Patrick