Can you install two sound cards?

Can you install two sound cards? I'm interested because I've been using Skype (an Internet vocal communications program) and I want to separate the audio generated by Skype from the rest of the audio. In other words, I want to set it up so that only the voice of whomever I'm chatting with comes through the headset (which I'd have plugged into one sound card) and the rest of the audio coming through the desktop speakers. Under Skype options, it is possible to configure through which device that the audio is to be output, however, since I only have the one sound card, that is the only option I can choose.