Can I access info. about this agreement at an IRS website?
If you efiled your return and it was included then you don't mail it in. It takes the IRS 6 weeks or more to send you notification of acceptance or denial of the installment agreement. Be prepared for the debit to happen anytime.
If you want to talk to someone at the IRS, you could try the following. (Thanks to SuperUser epo39b for figuring out most of this sequence.)
Call the IRS at 1-800-829-1040 weekdays from 7am to 7pm local time.
At the first prompt press 1 for English.
At the next menu press 2 for questions about your personal income taxes.
At the next menu press 1 for questions about a form you have already submitted, your tax history, or payment.
At the next menu press 4 for all other questions about your tax history or payment.
At the next menu press 2 for all other questions about your tax history or payment.
There will be a brief pause. When it asks you to enter your SSN or EIN to access your account information, don't enter anything. After it asks twice, you will get another menu. Press 2 for personal or individual tax questions.
It will then put you in the queue for a live agent, and tell you the estimated wait time.