Then this two page PDF from AICPA.org is just the ticket.
From the link:
Practitioners know that e-filing tax returnshas advantages: It documents the filingdate, reduces time at the post office, andsaves postage. For additional convenience,consider having business and individual clientsenroll in the IRS’s free electronic paymentprogram, known as EFTPS. EFTPSallows businesses and individuals to payfederal taxes via the internet or over thephone. It eliminates the hassles of writingchecks and taking them to a financial institutionor mailing payments to the IRS;payments are withdrawn directly from anenrolled bank account.