You'll definitely want to check with your company, but I could imagine that you will be looking at a few of these responsibilities.
- Install software
- Map network drives/printers
- Troubleshoot general computer issues
- Maintain updates/virus definitions
- Redundancy
You're basically helping people out with any issues that may come up with their desktop. Most of the questions you'll laugh at while others you may need to jump on SuperUser.
I would suggest using Group Policies on the Active Directory Server if possible and if that's what they're using. You can configure their network to automatically map network drives, printers, desktop settings, etc. Symantec Corporate Antivirus has a management software that will allow you to silently update all computers.