i use a terratec pre-amp easy to setup,plugs into your usb port and has some nice software with it,allthough i use a program from maxics to do the final track cuts.total cost about £90 but the results are brilliant so far done 41 cassettes and 25 lp`s with another 50 lp`s to go and some reel to reel stuff.
Yes, but if you have a hi-fi it's already built in. You can get the output from your hi-fi pre-amp if there's a "line-out" socket, and connect it to your PC sound card. This will be at a constant level, so will not be affected if you're also listening through your hi-fi and you adjust the volume or tone controls.
Or, if your hi-fi has a headphone socket you can use that instead, but its output will be affected by the hi-fi volume and tone controls, so don't fiddle while you're recording.