PowerGramo records your Skype conversations in real time, and lets you export them to MP3, so you can listen to them whenever you need to.
It works with Skype up to version 4.x, and it's compatible with Vista. Some of its features let you adjust the volume when you are exporting a voice call, and even save the text in a conversation.
Finally, you have to know that before being able to use PowerGramo you have to give the corresponding permissions to Skype; still, the process is very simple. Once it's installed on your computer and you start Skype, a pop-up window asks you to give Skype permission to record the conversations. Once you accept it you can start recording your voice calls every time you need to.
Trial version only lets you record 1 minute on each conversation.