If you're not in Taiwan and thus waiting for the OTA HTC Hero Android 2.1 update to drop from carrier Chungwa Telecom, you'll be pleased to hear that there's already a hacked ROM suitable for any Hero out in the wild. Master ROM-fiddler Paul O'Brien has released three different versions of the update.
Two are rooted (one of which has the Chinese-specific functionality stripped out as well, and is the recommended path for most users to take) while there's also an unrooted version. We're keeping a watchful eye on HTC's European support sites, and have a request in with their PR team for any public timescale they may be able to give.
Update: We've just heard back from HTC's UK PR team, who say that they expect the Android 2.1 firmware for the HTC Hero to be released sometime in June 2010. Nothing more specific than that, sadly.