First off, I would like to say that I strongly agree with BlairHippo and a few other people who have already expressed themselves. I will try to elaborate or else emphasize (by quotes,) without repeating too much of what has already been mentioned.
BlairHippo said:
"He couldn't make production-worthy
code with it, but that wasn't his job
-- his job was keeping all the big-picture design decisions on track
and preventing the technical team from
having to deal with any levels of
management above him."
I would say that it depends a lot on the hierarchy of the company and what the position in question entails. Some like to combine the role of technical lead and manager into one, in which case I believe one needs to have both strong technical and management qualities. People of both qualities are extremely rare, which is why, in my opinion, it usually makes more sense to separate these two roles as much as possible.
Corin said:
"That is not to say that knowing the
technology in use isn't beneficial.
That just means you're better able to
understand the team sooner."
For your team members to "accept" you as their manager, your assigned responsibilities should not exceed your qualifications. You need a certain amount of people and communication skills to effectively handle responsibilities such as; representing your team in a production circle (which might consist of a lot of specialized teams), organizing meetings, initializing conversations, helping out with practical problems around the office, "shielding" your team from unnecessary interruptions etc. Basically, doing all the things you don't want to do as a programmer.
tzenez said:
"The job of a Project Manager is to
take care of all the annoying little
things, like whiny upper management,
like make sure we don't loose contact
with the server, like replacing my
chair when it accidentally breaks so I
can get right back to coding. Its to
deal with all the things that need to
happen so your development team can
develop."