You have the option of chosing to file as a sole proprietor or as a Corportion.

If you prefer to file as a corporation instead of a “disregarded entity” Form 8832 must be submitted. Otherwise, you don’t need to file Form 8832.

Single person LLCs file the same as a sole proprietorship….on your Schedule C of your personal 1040.

If you are going to owe more than $1000, yes you should have been making quarterly estimates. It is too late to do that now for 2006 and the 1st estimate for 2007 is due 4/15.