
I'm more of a Maccy type than a PC type, but I get asked this question a lot, so I have done some research. Try www.dBpoweramp.com for music conversion and CD ripping software, encoders like FLAC, LAME and Ogg, LP encoders like RipVinyl. Some are freeware, some cost... but you'll be hard pressed to spend more than £50 for the whole lot.
Take this with a large pinch of salt, though. There are people here with hands-on experience who will steer you better than I.
Regardless, you'll need a two phono to minijack lead (designed for connecting an iPod to an amp) to connect the tape outputs of your amp to the PC (or better yet a digital audio connection... check your PC and hi-fi manuals for compatibility).