IT help desk job description?

It will vary according to the actual job, of course, but generally:

- answering phone calls from end users (say whether mainly internal or external, if they're a specific group etc)
- answering email from userbase / customer base
- creating tickets using some form of ticketing software
- using provided documentation and utilities to find information
- using provided tools and techniques to determine and sometimes resolve specific faults
- using logic and accumulated knowledge to determine and resolve minor faults and user issues
- creating documentation
- providing general IT assistance with relevant systems
- general idea of the size of the userbase
- general idea of the geographic spread of the userbase (national, international, five time zones, citywide, one building complex etc)
- approximate dress code (not absolutely necessary, but it helps)
- SALARY OR HOURLY RATE (fixed amount or a range, negotiable or non) - this is a big one. If you don't provide it, you won't attract the most efficient and effective top talent
- hours of support including any on-call hours and shiftwork
- location, at least down to the city, if not an even smaller area (CBD, west beach, SmithJones Industrial Park etc)
- your contact details by phone and email. Bonus points for Skype, Twitter, website with info request form.

(Optional, if relevant)
- training end users (over the phone, one-on-one, workshop/classroom as appropriate)
- monitoring IT infrastructure
- providing deskside assistance
- providing walk-up assistance
- some travel involved
- extensive travel involved
- telecommuting available up to N days per week/month
- occasional rotations into teams X, Y and Z for cross-training purposes