PPCGeeks - Windows Mobile + iPod Touch calendar sync

Hello. I currently have an HTC Titan (WinMo 6.1) phone, and I manage my personal calendar with the built-in outlook calendar. I do NOT sync with my PC currently. I currently keep all of the appointments for both my wife and myself in this calendar. So for her to know what's going on, she currently asks with me.

I am thinking of getting her an ipod touch for her birthday coming up. Does anyone have any ideas for how to integrate both devices so they can share a calendar? I am not very familiar with the ipod touch, but I am guessing that to sync our calendars, we would need an online app, perhaps Google Sync? We both use GMail for our personal e-mail. We would like to share a calendar, but keep e-mail completely separate.

Does anyone have suggestions on a good way to do this? The more transparent the better. Optimally, everything would sync over wi-fi, and would not require hooking any device to a PC. It would be nice if we didn't have to do any syncing manually! Thanks!