PODCAST QUESTIONS UPDATE: Various questions are answered! First, have I considered doing a podcast using Apple's GarageBand software, now that I have a Macbook Pro? Yes. Haven't done it yet, but I've fooled around with the software a bit, and it's enough like Acid that it's easy to figure out.
What kind of microphones do I recommend? Good question. If money's no object, an ElectroVoice RE-20 is a good way to go. I don't use those, because money is an object, and besides I already have some other mikes. I use an AKG C3000, and Helen uses a Marshall MXL microphone. For guests I've used an SM-57 because I have several of those utility mikes lying around, but I've just recently bought this Sennheiser on my brother's recommendation. I love the SM-57 as an instrument mike but I've never been crazy about it as a vocal mike. For vocal podcasting, most any microphone is okay, but ideally it shouldn't have too much of a proximity effect -- in which low frequencies are boosted when you're close to the mike -- because people you're interviewing tend to shift around. Whatever you get, use some kind of pop screen and you'll improve your sound a lot, at low cost.
For sound treatment -- the new podcast space is a bit echo-y -- I had planned to stick up some Auralex foam, but an InstaPundit reader who's at Ready Acoustics offered me a customized sound treatment if I'd do a review. I've gotten some of their bass traps and high frequency panels via FedEx now, but haven't put them up. I'll let you know how it turns out -- they're almost certainly overkill for the space, but it should be interesting. The 3D graphic of the room that they constructed after I sent them photos and measurements was kind of cool, too.
If you're starting from scratch, you might want to consider a podcasting kit like this one. I haven't used it, but it's probably quite good, and quite reasonably priced. It says something about the popularity of podcasting that many music dealers and manufacturers are offering products aimed specifically at that market. An earlier post on this topic can be found here.
UPDATE: Tom Spaulding -- who as John Fogerty's guitar tech has lots more audio cred than I do -- writes: "I love the M-Audio gear I own. Check this out: M-Audio Podcast Factory." Looks like a good, cheap solution. I actually use the Mobile-Pre USB audio interface myself. It's a bit noisy for music applications, but fine for voice.