[jayec]

I think you should always try and network, you never know where your next opportunity will come from. Don't worry about people being resentful of your promotion, someone obviously thought you were good enough to do the job. Prove them right and you'll have nothing to worry about. The best way to move up the ladder is to probably get to know your manager's boss better since he's the one who promoted you in the first place.

I know a lot of people say that once you start managing people that you don't really do a lot of the technical work anymore. Personally, I love coding and if the technical side of things is something you enjoy then just make time for yourself to do it, even if you're only working on small things as part of your team. The other developers will see you in a better light as well if you're helping them with their day to day work.