I have a employer identification number (EIN) what tax form do i use to file taxes?

Unless you formed another legal entity such as a corporation you just file the income and expenses on Form 1040, Schedule C. You show both the EIN and your SSN on the Schedule C. If the net profit is $400 or more, you attach Schedule SE to figure the self-employment tax. You don't technically need an EIN if you don't have employees, but it's a good idea to get one anyway as you can avoid scattering your SSN all over the place by using the EIN for business.

if you are a sole proprietor and don;t have any employees, you can just use your soc sec # and file a schedule C and SE with your 1040 tax return (don't forget to also file a state tax return for the business income)

You have to file form 1040 + schedule C (profit and loss from business). Of course, use professional tax preparer for your taxes. They know what you will need.

Go to IRS.GOV and download a Pub 17 to study up on taxes so you have an idea what it is you are doing. If you have no good grounding in math and legal matters you might consider going to a tax preparer who has studied the law and tax changes and can prepare a correct return for you the first time out of the chute. Never try to fly a plane unless you have a lot of training and experience under your belt.

Unless you have employees, you very likely didn't need the EIN, but having one isn't hurting anything. And if anyone who is going to pay you gives you a W-9 form to fill out, you can use the EIN rather than giving them your social security number. I assume your business is a sole proprietorship. You'll file a form 1040, with a shedule C of C-EZ, and schedule SE. Use your ss# on the forms, not the EIN, for tax id.

you can use the EIN or your SSN for filing Sch C on your 'side jobs' if you don't have employees or are incorporated, you did not need an EIN since your income is at least $5000, you will have self employment tax to pay, on Sch SE, all included with your 1040

IRS doesn't just "give you" an EIN. You have to APPLY to it - and it's used to report tax information on your employees, if you have any.