I'll tell you how I do it. I have a Mac, and use a program called Amadeus Pro. I also have a CD recorder as part of my component stereo system.
1) Record the record onto a CD, one continuous track per LP side.
2) Use Amadeus Pro to read the CD.
3) Using the graphical information shown in Amadeus, split the tracks into individual files. Here you can also adjust the volume levels if they're too low.
4) Once done, import those tracks into iTunes and enter the correct information (performer, song names, etc.).
It's a time consuming process (honestly, it's sometimes easier to just buy the digital version of the album), but it's so much fun to carry your records around on your phone.
Perhaps others have an easier way of doing it, but this is how I do it.