Is there a way to tap into this functionality from bitcoind? I have a cron job set up to check my 'expected incoming addresses' for changes in the balance, but cron has a resolution of one minute which is pretty crap for this kind of thing, and I would prefer an event-style code-base where possible rather than a scheduled-task-style code-base.
Any tips on how I can tap into this to trigger some other event as soon as an incoming transfer is detected from bitcoind?
You could setup an agent at bitcoinmonitor.net to monitor the 'expected incoming addresses'. You can get email, http callback or jabber notification immediately when you receive (or withdraw) any fund. Side effect is you don't have to have bitcoind running to get notifications.