How can I record interviews (phone and otherwise) to post online?

I co-host a podcast. I use Skype and Audio Hijack Pro. I then do some editing in Garageband and post the files on Amazon S3 using Transmit. I’m sure there’s equivalents on Windows but I don’t know what they are…

On windows use Skype Call Recorder with Skype. Recording both ends of the call and mixing them together can help get a cleaner sound. Adobe Audition can be used for mixing on windows, or Audacity as a free alternative.
If your on a mac do what Tim says.

Whatever you do, make sure you do it legally.

I’ve started using CallGraph for Skype. It’s a free extension to skype and is very user friendly. It works for PC (don’t know about MAc) and it only records Skype sound (you and your caller). Does not record any other sounds from your PC.

Every week I record the supervision meetings (for my own reference) that take place between me and my PhD supervisor who is on sabbatical at the moment. I use exactly the same software as @timtrueman – I use Skype for the conversation, and Audio Hijack Pro to record it, and it works extremely well, it’s very easy to do, even for someone like me that knows almost nothing about audio recording. If you use a Mac, I would strongly recommend this approach if you are wanting to record phone conversations, as it requires no extra equipment (providing your computer has a built-in microphone) and is very straightforward.