Both LLC and S-Corp are pass-thru taxation. S-Corp requires an application with the IRS and I had $0 revenue when I formed my holding company as a Sub Chapter Corp... You will need corporate by-laws, annual reports issued to your state, etc though. Which sounds alot more complicated than it is. Really its quite simple.
My preference is S-corps because you can avoid self employment tax if you're racking in some cash after you pay yourself a "reasonable salary" which the IRS does not define. we see salary as 50-80% of profit, and the balance "dividend" is not subject to self employment tax.
A great resource for general small business info is SBA.gov. An attorney will cover any start up info and get your liability buttoned up.