Alistair's blog\wiki has a set of specific one liners from programmers - to newly minted team leads.
My 3 favorites were:
Whatever their job is, help them be better at it.
You are now a junior person in a brand new career that you never were trained for – and keep in mind that the medium you are working in is PEOPLE.
People will bring you their issues with teammates – it will help to give your people some training in how to deal with those issues themselves.
Notice that they all talk about the idea that you are working with people, and that driving people to be better, and caching them to solve their own problems is important.
Now, here are a couple that I didn't like:
YOU ARE THE ABSTRACTION LAYER – you provide the Bubble of Happiness.
Only to a certain point. Once your team is ready to face challenges, it's OK, and even welcome to start letting them deal with real world stuff - how do they handle outside interference? what happens when a higherup asks for a small feature really quickly?
A mature agiel team should be able to handle these, but don't try to let them handle it if you're all still learning the territory. It's OK to have an "incubator" where the team lead only gets all the "heat" from the outside, but that doesn't mean that a team can't go and face their real customer and see what their all about.