A service I've been using for cheap web hosting servers without cron access is a free service called webcron. However I just got an email from them today sayign they'll no longer be free:
The downside of this improvements is the free account that will no longer be available.
I was curious if anyone knows of any acceptable alternatives?
Don't be so cheap, when they are. ;) http://www.webcron.org/content/view/13/58/lang,english/
For €1 you get 10000 jobs. That is probably cheaper than the electricity bill you would get if you had your own server doing the webcron for your sites.
You could set up a cron job on Google App Engine, which is free up to a very reasonable quota.
http://code.google.com/appengine/docs/python/config/cron.html
You could use a tool like WebCron:
http://barebonescms.com/documentation/webcron/
Basically, it fakes 'cron' on hosts that don't provide access to a task scheduler. All code resides on your server, thus no need for a third-party.