As a professional DJ and producer who has done the whole conversion of vinyl to mp3 I would suggest using the following software

1. Soundforge

1. Audacity
2. Cool Edit Pro

Aufacity would work fine though, simply make sure you are using either the ins from your sound card and not your mix input. You also want to make sure that you are recording as close to 0db without going over (clipping). My general rule is to record to -3db with a software based limiter and then normalizing the audio to 0db post recording (after saving the original file)

Adjust your input volume from your recording device by right clicking on your audio device and selecting the properties of the recording devices, muting all but the selected input and adjusting the level while watching the monitors for volume. There should be an option in your software to monitor while recording.

Note also while recording vinyl (I'm sure you know this) do not go from your turntable straight into your sound card. Obviously turntables are phono and without going through a proper grounded pre-amp its going to sound gnarly.

I took it a step further and use Final Scratch 2 to record my vinyl. Its an audio interface via firewire designed to allow you to control mp3s via timecode vinyl. However the passthrough allows you to record your record collection perfectly as heard.

Do not even consider the USB turntables for recording as they are the biggest rip off since the pet rock. I would also suggest using Ortofon Carts and Needles for recording. You want best sound-reproduction and the lowest quality cart I would even consider would be a shure M447,