I have blogged indirectly about this before: using page2rss.com to create a RSS feed that updates the reader a site changes. Among other things, I have been using this for Economics Research Network's Professional Announcements, and this works quite well save for the hard to read formatting. Here is an example of what the RSS feed looks like:
This is rather difficult to read, but it serves its purpose of alerting me to new conferences or job postings that went up on ERN. For email alerts, you can use this together with Yahoo alerts – which you can setup to have an email send to you when the RSS feed updates. However, I have been having issues with that Yahoo service (previous blog posting on this topic).
The two ERN links I check are:
http://www.ssrn.com/update/ern/ernann/ern_ann.html (http://page2rss.com/rss/1cc62dfaf49c436e2da76ef98ed4c53e)
http://www.ssrn.com/update/ern/ernjob/ern_job.html (http://page2rss.com/rss/33f5a81d12a753bc9c2bf9b99602ee87)