I was investigating the Amazon EC2 Cloud computing platform for work, and spotted that they have a 'free tier' http://aws.amazon.com/free/ which allows a single 'micro' virtual machine to run for a year without any charge! I've set up a Linux instance and installed prpnet (tis a bit of a pain as you need to install g++ and build the p7zip tool yourself to unzip the prpnet package), and it appears to be running great.
Currently it's taking in the region of 5-6 mins per test on the PPSELow port - which is not surprising since some benchmarks indicate that a micro instance gives you about 1/3 of a Core 2 Harpertown core.
Feel free to try it (but don't complain to me if you run up a charge on credit card :)
Proud member of team "Aggie The Pew". Go Aggie!
3073428256125*2^1290000-1 is Prime!