What I want to do net is to set up a server that I can dial into over my cellphone when I am away from the office and become part of the network
From my understanding, mgetty will do the job here.
Mostly it will be on an internal pabx line for testing purposes, and will give a basic 33.6k connection to the network. other than the obvious security risks, and slow speed, are there any pitfalls I should be aware of or better tools/methods I should consider.
As another solution, you could use your cellphone (or any phone you are handy to) to dial into the commodity Internet, and run a VPN such as IPSec or encrypted PPTP over the Internet back to your home network. One benefit of this is that most ISPs have toll-free dialin, so you won't be paying a toll call to connect to your home network (and therefore wouldn't be a problem just borrowing a handy landline).