As part of a recent study I ran at University I had to interview some people. I did it over Skype because the participants were from various locations around the world, and so that I could easily record our conversations.
To do the recording I used Call Recorder, a commercial application which offers an unrestricted 7 day trial. Once that period had expired I just created a dummy user account on my OSX laptop, then installed it for them using the same Skype username: Instant 7 days more free use.
Once I’d recorded the interviews as .MOV files with a separate audio track for myself and the interviewee I then mixed them down to MP3s using FFMPegX, a shareware frontend to the command line ffmpeg.
To do the transcription I used Transcriber, a FOSS package that I initially ran on Windows, but since I’ve moved to Ubuntu I’ll use it here in the future.