iPod Touch Syncing

My wife and I are hoping to each get an iPod touch to sync our iCal for our day to day schedule. Are you able to 1) input new data into the calendar right from the ipod (pretty sure you can) and then 2) sync that back to the computer? Also, mostly I'm wondering if you can sync from one to the other via the wifi. So if she puts in that we have "dinner with Mom & Dad Friday night." are we able to get that onto my iPod right from hers? Then we can only have one iCal going, and we'd just update it as we go.

THanks