What do I need to consider tax wise being sub contracted?

You will report your income and business related expenses on schedule C or C-EZ (Form 1040). Then you put net income (or loss) on line 12 of Form 1040. This income is subject to SE tax at 15.3% (this is shown on line 57 of Form 1040).

Most of the self employed people, the easiest option is to make quarterly payments equal to one fourth of the tax for the previous year. For making estimated tax payments for the year 2010, divide your total tax for 2009 (or it may be 110% of your tax for 2009) by four and send the quarterly payments of the estimated tax using Form 1040-ES. If you use a tax software for your 2009 return, the software will automatically generate estimated tax payment vouchers with the amount filled in.

Yes you should pay quarterly with form 1040-ES