Jay writes "RSS feeds are now available for individual archives and categories from arXiv. arXiv
is an e-print service in the fields of physics, mathematics, non-linear science, computer science, and quantitative biology.
"This is an EXPERIMENTAL service and may be changed without notice. Send comments to www-admin@arXiv.org. (5Aug2003, updated 30Mar2004)
Daily updated RSS news feed pages are available for all active archives within arXiv. The URLs for each archive are constructed by appending the archive name to http://arXiv.org/rss/. For example, the URL for the RSS page for the Computer Science archive is http://arXiv.org/rss/cs.
News feeds are also available for individual subject classes of archives that have subject classes. A specific subject class is selected by appending a period (.) and the subject class letters to the URL. For example, the URL for the RSS page for Mathematics -- Quantum Algebra is http://arXiv.org/rss/math.QA".
For more information, see "RSS News Feed for E-print Updates"