There's a dozen or more possible causes, but my bet would be on that crappy plastic bushing on the right hand side of the clutch pedal linkage - junk. The second place I'd look is the clutch master or slave cylinder, one of them could be going bad. Check the fluid in the master cylinder first, found out the hard way, brake fluid will take off your paint. How old is the clutch and has it been replaced? May also want to check your firewall for cracks but I've never seen it in one that new. Those are the easiest external fixes, don't want to get into the internals.
cfpinz
Edit - There's a bleed screw on your slave cylinder, mine came loose one time and let fluid seep out, acted like what you are describing.