Maintaining Technical Depth
Mark Richards has an excellent short presentation on developing and maintaining technical depth as an architect. His primary point is that nobody can be an expert on everything, but an architect should at least be aware of the existence of the most important tools for solving a wide range of problems - including new ones that are becoming popular.
He recommends starting each work day with 20 minutes of research, before reading emails. He also suggests some sources of info:
Sounds like good advice to me.