It's weird, I was just wishing for this the other day (while late for an appointment with no idea what street number the building was). GooSync is a mobile application that synchronises with your Google Calendar, including all-day and recurring appointments in the free version.
There's also an Advanced option that lets you tweak the synchonisation settings and sync multiple calendars, which costs £19.99 for a year. There's a big range of supported mobiles on the site too, it's not just smartphones.
It sounds great, although I've got a sneaking suspicion that sooner rather than later Google will launch a Yahoo Go-style application combining Gmail, Calendar, search and maybe access to your Google Docs. Whether GooSync will still appeal then remains to be seen.
(via the::unwired)