Is it possible to have a task (defined in a plugin) be scheduled in Craft to run on a recurring basis without having to use cron?
If so, where do I put those settings (eg, to run a task hourly)?
Currently not... after all, the task has to be triggered by something (either a cron job or a PHP request to kick it off).
We've discussed the possibility of adding quasi-cron support natively in the future. It wouldn't be 100% accurate, though, since it would still require a PHP request to trigger it. At most you'd be able to say something like "Start this task at 8PM tomorrow", but it wouldn't actually start until the first PHP request that occurs after 8PM tomorrow.