Biowulf

Biowulf Platform service website that lets you blast lots of sequences on their servers

q The NIH Biowulf cluster is a GNU/Linux parallel processing system designed and built at the National Institutes of Health and managed by the Helix Systems Staff. The system is designed for large numbers of simultaneous jobs common in bioinformatics as well as large-scale distributed memory tasks such as molecular dynamics.

http://biowulf.nih.gov/

This service seems to be restricted to NIH employees and contractors. The service costs $30/month.