split lickety

i recently created a website on my home box with IIS. i'm running XPpro. its easy to use and it works great. what i'm wondering is if anyone out there can give me a clue as to what security risks i'm running. i have anonymous browsing enabled so i can share files with people in forums such as this one. the only firewall i'm running is the one that comes with XP. am i at any more risk than anyone else with a constant internet connection? i figure my lack of a real firewall is my main prob but i just don't know that much about what is possible for a hacker to do. i hope this is enough info for you guys. any feedback would be helpful. thanks. split.