My chairman, Samir Khuller, asked me to post our job posting for a lecturer to my blog, so I and doing it right now. I think he overestimates the power of this blog.
At Univ of MD at College Park lecturers teach most sections of our intro sequence (CS1, CS2, CS3, Discrete Math). They might sometimes do a higher level course if the need arises. They are there to mostly teach and advise students, not do research, though some do and that's certainly fine. Some have PhD's and some don't. Note that this is a full time job--- these are not adjuncts or rent-a-profs. They are part of the department.
Is having lecturers teach the intro courses a good idea? Overall YES; however, I would like to have professors teaching those courses once in a while, or be involved once in a while, as they may have a good idea to share with the lecturer (then again, they might not). Having said that, you don't see me volunteering for CS1, CS2, or CS3 (My policy: I never teach a course where I would get a B if I took it. One exception- I did once teach Graduate Algorithms and got in a bit over my head.) I do teach Discrete Math once in a while. I also like to proofread the midterm and final of whoever is teaching it. I'm NOT that good a proofreader, but I like to know what they are up to and it gives me an excuse to talk to them about the course and make sure it doesn't drift to much. I would like to think I have a good rapport with the lecturers.
Does having a PhD in CS and being a professor give one some insights on what should be in CS1,2,3 and how to teach it? I honestly don't know. My first semester at Univ of MD (1985) we were teaching program verification in CS1. I knew immediately it was a bad idea and eventually (without any input from me) the dept stopped doing that. This is a case where being a researcher may be a negative with regard to education.
I would like to think that my working in theory helps me teach Discrete Math. It does as a source of some problems (e.g, if a paper says `by an easy induction...' that can be a problem set) but one should not get to carried away and go over their heads.