iCal has this annoying trait of automatically sending emails to the originator of “events” in Apple speak. You don’t really get a choice as to whether or not you actually want to send the email.
I had just about resigned myself to manual entries in iCal for this. The new iPod update for the Touch 1.1.2 will now let you enter “events” on the device. A good thing. But somewhat unwieldy for quick entries. The keyboard app on the touch, like the iPhone takes some effort to use.
Just on a whim, (almost an afterthought) I cruised the Apple forums. I found this thread:
http://discussions.apple.com/thread.jspa?threadID=1206182&tstart=0
And in that thread I found this jewel: hptt://www.nhoj.co.uk/icalreplychecker
iCal Reply Checker is a handy little app that tags along with iCal and lets the user decide whether or not to send a reply, not iCal! Coolness...