I use a calendar app called Calengoo, because it has a snooze function for the alerts (stock iCalendar app doesn't). The trouble is the option to snooze only appears half the time. Also, if more than one alert happens before you dismiss the first one, the awknowledgment of the subsequent ones doesn't work. Also, Calengoo has an option to re-alert every minute in cae you missed the first one.
Honestly, I find the iTouch pretty bad as a reminder-device. There are strange holes in it's functionality like lack of snooze or re-alert. There's also no graphic EQ, strangely. People have been complaining to Apple about those things for years, but Apple ignores it.
Whenever I get the money, I plan to get an Android device. I do find the iTouch a nice music/podcast player, though.