I bought a mixer on my trip to London a few days ago - an Alesis Multimix8 USB.
Among its many features are 8-channel mixing, 4 microphone/line inputs, a load of special effects as well as phantom power for a condenser microphone. Full specs here. Bundled with it is Cubase LE recording software. That's primarily intended for music mixing and I'll probably stick with Audacity for podcast voice recording.
I bought the Alesis at Maplin Electronics in Bayswater for just under 130 quid, along with a Shure C606 dynamic cardioid microphone. It all looks to be more than ample for what I want to do with audio recording for podcasting, at least at this point - an affordable hardware-based recording and mixing system that's easy to install and set up and isn't too complicated to figure out and use.
Installation was very easy - turn it on, plug the USB cable into the PC, turn on the PC and that was basically it. Windows XP saw it immediately and, after changing the default recording/playback settings in the control panel audio setup, I was good to go.
So I've been experimenting a bit today, and learning (or trying to at least) some new things. I'm sure I don't yet have the optimum settings for standard voice recording - this 5-minute test recording (MP3, 2Mb) might indicate that - so more trial-and-error testing ahead. I plan to use it when Shel and I record Monday's edition of For Immediate Release: The Hobson & Holtz Report.
One issue I may encounter - echo when recording over Skype. Shel and I have had this problem for a while in our twice-weekly shows. The echo doesn't record but I certainly hear it. We think it's a mixer issue. So I wonder what will happen on Monday when I'm using this mixer and Shel's using his and we're recording over Skype...