You should want to start out in helpdesk when breaking into IT. You have to have an understanding of how Group policy, AD, Exchange, SQL, application servers, and a plethora of other systems and networks affect the end user.
Edit: Also understanding a local pc to the registry level, how the registry can be manipulated to troubleshoot, how to command os' at the command line level.
Just my .02, I don't know of any Sysadmin, network admin, network managers that skipped starting helpdesk.
You pretty much have to start helpdesk unless you have some kind of hookup.
Nobody is trying to let some guy off the street with no IT experience into their server room.