[Callers] OT - Calling and US Taxes

OK, we all know we're really in this for the outrageous sums of money, right? ;-) But if you're lucky, you're finally at the stage where you're at least covering your costs and have enough gigs where you're concerned the IRS may expect you to be reporting your income, recording expenses, etc. I've looked into this somewhat and from what I can tell in the US, it involves making quarterly Social Security tax contributions on the income and including the income/expenses toward your estimated tax payments at the Fed/State/Local level. The trick is *how*. Does anyone have a pointer to a good tutorial or other tips/direct advice on the topic? (Apologies for the intrusion of the *Real World* into our magic place...)