Tssss....
It really is nobodies interest that your question is newbie. What is of importance though is that by reading the title of your message we can deduct what the question is about. I really can't understand why you would fail to see that. Newbie or not.
Anyway, to answer your question: Yes, you can and yes, it's easy.
It's called dualbooting and a google for 'dualbooting XP and Solaris' should come up with several hits.
First install XP on disk A (it's probably allready there) then go trough the Solaris install and select the second disk as your install media . Solaris should recognise that you have XP on your first disk and should therefor automatically implement a menu at boot after install. This menu allows you to select either to boot xp or Solaris.
..This all under the assumption that controllers and disks are all supported according to the HCL.
Good Luck