As an owner of LLC - if you did not select the LLC to be treated as S-corporation - you need to verify that with your tax person - you are not considered as an employer.
LLC should not pay wages to the owner and should not run payroll - if you do so - that is incorrect - and should be corrected as soon as possible.
As an owner of the LLC (not as an employer ) you are responsible to keep a business record and report LLC's business income and expenses on your personal income tax return.
You file your federal tax return annually - normally by April 15 following year.
Separate issue - when your tax should be paid - generally the IRS expect taxes to be paid as the income received - there are several ways to pay your tax liability;
-- you may ask the payer to withhold taxes - or if you have a regular job - you may increase withholding to cover your business tax obligations.
-- you may pay estimate tax quarterly - see form 1040ES - http://www.irs.gov/pub/irs-pdf/f1040es.pdf
-- you may pay taxes at the tax time - for 2009 tax year before Apr 15, 2010 - however - if you do not pay enough tax, you may have to pay a penalty for underpayment of estimated tax. Generally, most taxpayers will have paid enough tax to avoid this penalty if they owe less than $1,000 in tax after subtracting their withholdings and credits, or if they paid at least 90% of the tax for the current year, or 100% of the tax shown on the return for the prior year, whichever is smaller.