Bitcoin mining pools are like lending / borrowing cpu time, but it's only for hashing. Is there something more general; a market where you can lend and borrow cpu time, disk space and so on?
Maybe not exactly what you are asking for but CoinLab have a mining pool that intends to use the computing power of their members for jobs other than hashing.
From the Bitcoin talk forum topic:
We’ve identified a number of opportunities to monetize our growing GPU cluster at a higher rate than Bitcoin mining, particularly for NVIDIA cards: Protein Folding, Computational Finance, and Big Data Analysis, just to name a few.