It really depends on what all you want to record, and what all instruments are involved. These days, you really can do a lot with very little. Here are the essentials at a very minimalistic, basic level:
- You obviously need something to record onto. Remember that recording audio and editing takes some power from your machine, and your computer needs to have the RAM and power to do that. It all depends on how much you want to record and what all instruments you plan to work with. There are many factors to this. Right now, just make sure it runs OK. What kind of computer are you using?
- This is also called your DAW (Digital Audio Workstation.) There are TONS of different programs out there, some of which you can find for free. You have Pro Tools, Logic, Cubase, Nuendo, Reaper, and many many more. I use LOGIC 9 and find it to be very easy to use and complimentary to getting a great sound easily.
- This is the gatekeeper between your instrument and the computer. There are tons of companies making these including M-Audio, Line 6, Pre-Sonus, MOTU, Alesis, Digidesign, and many, many more. You can get a good interface for $100 bucks onward.
- You need to hear what your doing. A decent set of computer monitors will do, but you can find some decent monitors for pretty cheap that will aid you in finding the best sounds. These are what play back your recordings.
Cables, Headphones, Etc.
- You will need all the necessary cables and so forth to get moving along. You need mic cables, 1/4 inch for your guitar, USB or Firewire for your interface along with some headphones. Some times you can find package deals that include all this stuff.
- With anything, it takes time. Just because you have all the gear doesn't mean anything. There are plenty of people whom have great stuff and there recordings sound like trash. On the flip side, there are people with little to no gear that seem to make things sound amazing. It will take time and patience, but you will make it work.
Hopefully this helps. These are the bare basics. :)