Is ANYTHING open in Rome on Monday - ie. Forum, Colosseum?
What about Sunday - is that a normal day with things open?

All tourist sights are open on Sunday

Forum and Colosseum also open on Mondays

Thanks. Pantheon?

Monday (except holidays) is fairly "wide open". Some restaurants use it as a day off.Even on Sunday many sites (Forum,Colosseum,etc.) are open. Some sites (Borghese, Ostia,etc.)are closed Moinday,but open Sunday.Times vary based on the season.

Pantheon is open daily

do you think these places will be open on new years day?

No, the Colosseum and Forum are both closed on New Year's day. The Pantheon may be open as it is a church and there are usually services that day.

Check museums' timetables. Most are closed Monday. Capitoline Museums are closed Monday and New Years day, and close early Dec. 31st.

Monday is the day you do the free things. Spanish Steps, Trevi Fountain, Forum, Trajans Market, Colosseum (not free),Pantheon that should keep you busy <G>
Another fun thing is to just hop on a bus and ride around Rome or take the #8 trolly and ride to end of the line near it you will find a huge local market place thats great for a stroll.

Ahhh..what about in Venice? Will anything be open on January 1? (as you can see, i still don't have my itinerary figured out!)

http://www.planetware.com/tourist-at...ome-i-la-r.htm
This is a great site for getting info on attractions. As you'll see the Colosseum is closed Jan 1. If you check Venice you'll see the Doge's Palace is closed Jan 1 too. Not a good day for attractions.

St. Mark's Basilica in Venice is open on New Year's Day. It's a national holiday, so most museums and public attractions are going to be closed no matter what city in Italy you happen to be in. Churches will be open.

Everything is open at the Vatican on Mondays, correct?

Everything at the Vatican is open on Mondays unless it is a national holiday like Easter, Christmas, New Year's Day and some other holidays. Check the schedule at vatican.va. Note that the Vatican Museums close various sections of the Museum at intermittent times but the popular sections like Sistine Chapel and Raphael Rooms are always open.