clutch failure

[FabricSign@aol.com (FabricSign@aol.com)]

This may be a dumb question but I don't know much 
about clutch and transmission.  I have an '84  8-valve.

Yesterday I noticed that it was getting more difficult 
to shift into 1st gear from neutral, and then from 1st 
to 2nd.  Today I managed to make it as far home as 
my driveway and suddenly couldn't select any gears 
at all -- clutch pedal down, with resistance, but won't 
let me engage gears while engine is on.  Gears shift 
fine with the engine off.  Clutch cable is adjusted to 
proper freeplay.

I'm not set up to do clutch work, so I'm gonna have it 
towed to a good shop, but I'd like to be forearmed with 
some knowledge.  Any tips as to what went wrong here
would be real helpful.  My baby is broken !! 

TIA
Leo