Jim as you may be aware, I typically suggest using a MixMinus solution with a microphone, mixer, and digital audio recorder to record Skype calls.
Earlier this year, I was interviewed by another widely known podcast consultant. He has always consulted podcasters to do just what you are asking, using a software package to record the call. He called me via skype and as I always do, I made sure to record everything on my end using the mixer, mixminus and digital audio recorder.
Here's what happened.
1) He called me on Skype
2) We had a great connection
3) I told him I was going to record on my end as well
4) I asked him how he was going to record, just to compare notes
5) He said he knows that I prefer non-software based recording for interviews but found that Audio Hijack works well for him.
6) He started the interview with me.
7) Five minutes into the interview, he got the spinning beach ball on the audio hijack software that he was using to record our interview.
8 ) He asked if he could call me back after he rebooted his system.
9) He called me back about 4 minutes later
10) We started the interview over from scratch (ALL THIS BEING RECORDED ON MY END PERFECTLY)
11) Several minutes into the 2nd attempt, his recording software crashed again.
12) He told me that this had only happened to him once or twice in the past, but "worked most of the time."
13) He asked if I would be willing to send of "MY RECORDING" of the interview to him for him to release in his podcast.
14) I was happy to do so.
15) We started the interview a third time and actually went all the way through.
16) After we were done, I transferred the recording to my computer.
17) I cut out the first EIGHTEEN MINUTES of the recording where he had issues with his recording setup for the intervew
18) I re-saved the audio file
19) I uploaded the file to my server and sent him and email with a link
20) He put the interview with me in his podcast and I have gained no less than 2,000 new listeners as a result of the interview and sold more than $9,000 dollars in podcast equipment as a result of the interview.
21) Imagine how much potential gain would have been lost for me if he were to rely on that recording solution and had to "reschedule" for another time, only to be lost in a sea of other to do items that might pull him in other directions.
I have about 19 other stories JUST LIKE THAT ONE from people I've done consulting for. The thing is, I put up with a lot of his technical issues because I'm in the business and I know what it takes to pull something like this off. Not everyone we interview will put up with 18 minutes of fooling with technology to get it right, or not get it at all. Those folks will not likely allow you a reschedule.
Worst stories are those where the software program INDICATED THAT IT WAS RECORDING PERFECTLY only to find out that after the podcaster just recorded the MOST AMAZING INTERVIEW IN THEIR LIFE where they got to talk to someone they would have never dreamed possible and had the most amazing 65 minute conversation ever, only to learn that either A, there was NO AUDIO recorded what so ever, or B, there was a huge screeching HISSSSSSSSSS through the whole recording, making it unbearable to listen to.
In my opinion, I'm not happy with doing exciting and important interviews that are hard to come by and depending on software recorders that only work 87% of the time.
However, I understand your question as you want to start out doing this without the investment in the equipment up front...There are a bunch of solutions for the Mac:Audio Hijack
http://www.rogueamoeba.com/audiohijack/Call Recorder
http://www.ecamm.com/mac/callrecorder/Nicecast
http://www.rogueamoeba.com/nicecast/WireTap Pro
http://www.ambrosiasw.com/utilities/wiretap/Here are solutions for the PCFreecorder
http://applian.com/sound-recorder/Hot Recorder
http://www.hotrecorder.com/i-Sound
http://www.abyssmedia.com/KishKish
http://www.kishkish.com/Pamela
http://www.pamela-systems.com/PowerGramo
http://www.powergramo.com/Total Recorder
http://www.highcriteria.com/