Do you mean video tapes or audio tapes? If you mean VHS or VHS-C videotapes, a standard VCR with a TV capture card is your best option (the only other option I know of is pointing a webcam at your TV, which is horrible, so yeah). You can get TV capture cards in PCI, USB, and ExpressCard forms. I have an HP ExpressCard tuner that works well with my new Vista laptop. Just hook the VCR's yellow/red/white connections up to your capture card and record.
For audiotapes, all you need is an audio Line-In and a tape player. Just connect the output of the tape player to your Line In jack using a male-to-male stereo minijack cord, commonly available at RadioShack or other similar stores. Then you'll need an audio recording app, Audacity is free and will work well, but even basic things like Windows Sound Recorder will do. It will most likely record to .wav, so you should convert it to .mp3 or whatever format you prefer after recording it. Audacity can use LAME, a free MP3 encoder, to convert your output to .mp3.
For DIGITAL VIDEO TAPES like miniDV, your camcorder should have a FireWire (IEEE 1394) or USB/USB2.0 connection. With these, you can just plug in and record from the camera to your PC in full digital quality. You may need an application capable of recording this input.
