What's the best source for incorporating a business?



I recommend using an attorney.

I set up a few myself in my early days - then I started wanting Nevada corps or Delaware corps for the tax & liability benefits and found that an Attorney doesn't cost me more than a couple hundred over what the regular State fees are and they will be your 'registered agent' or 'registered office' in that State for at least a year for free.

I think Attorney's are well worth their fees when it comes to filing all the reports, paperwork, etc.
 
I'd actually ask a good accountant. more comprehensive knowledge of tax benefits in my experience. Should run about 4-600 for the paperwork, not including any consultation.
 
legalzoom.com isn't bad, but you will overpay for their services being so easy.