once the new release system is live (about 4 hours from now *grin*) it'll finally be possible to have the modules page in core somehow notify you if any of the modules you are using are out of date and if new releases are available. i see 2 primary ways this could work:
- RSS based: once project.module is providing an RSS feed for all new releases (http://drupal.org/node/94138), it would be possible to have some kind of aggregator block that showed up on your modules page, that subscribed to the feeds for all enabled modules (filtering the feed for releases that match the core releases series you're on (5.x vs. 6.x), ideally filtering based on the major revision of the module you've installed (e.g. if i'm running 5.x-1.3, only tell me if 5.x-1.4 comes out, not if 5.x-2.4 is available).
- XML-RPC based: could potentially do more fancy stuff than simple RSS aggregation could, but might be overkill. for example, if it was XML-RPC based, i think it'd be easier to do stuff directly in the module page UI itself (like change the color of rows for modules that are out of date). if a security release was made, the row could become bright red and a huge [SECURITY RISK] icon could appear, etc... this would obviously require some project.module modifications to provide the XML-RPC server side that ran on d.o (which would be a separate issue, but i don't want to file that unless it looks like XML-RPC is considered a good approach to this one).
to be perfectly honest, i don't yet know enough about either RSS feeds or XML-RPC to have a strong opinion on which way is best, or if there are other, better options i'm not even considering. i'd love some input from others about this...