This weekend while I am home being scared and nervous, my work computer will be changed from XP-Pro to Vista. Should I stop being scared and nervous--or not?

Do not worry! Vista is barley any different. Its pretty cool. You have nothing ot worry about. You benefit from getting the latest windows updates and better protection and just some cool new features. The program runs pretty smoothly. It might take a few minutes to get used to it but other then that its worth it.

Staying with XP is fine as well, there both very good.

I read somewhere it has tabs like Firefox does?

That's IE7, which works for windows XP and Vista...

You're muddling up 2 things. Vista is the Operating system, not the web browser.

Yea ^^. ITs pretty cool, if you have a lot of web pages open or just a lot open in general, there's a button you press that allows you to go through each window choosing which you want to use. Its a useless feature but it looks so cool haha :D

Why are you worried about Vista?

I've heard and read only negatives about Vista, some negatives from people I know and trust.