You need to hire competent immigration counsel to help you with this complex case. Not the right time to experiment and try this on your own. The potential forms if he has only entered illegally once, and has never left would be I-130 intially and G-325 and once approved, come March 4, 2013, form I-601A and then he needs to go overseas and apply for a DS-230 PArt 1 and 2, in addition to forms I-864. I caution you to try to do this on your own without at least having a comprehensive consultation with competent immigration counsel. This would really be misguided and not smart. He's got the illegal entry and this makes matters complex.
The forms are readily available on the USCIS website. What you need, though, is an attorney who can help you navigate not only the I130 petition, but the I601 waiver which will be needed since your husband entered illegally and accrued unlawful presence.
Samuel Ouya Maina, Esq.
Law Offices of S. Ouya Maina, PC
332 Pine Street, Suite 707
San Francisco, CA 94104
You will need an immigration attorney to assist you. Depending on how your husband entered the U.S., it might be tricky. You will need to file an immigrant visa petition and a waiver application. You may be helped by the new provisional waiver of unlawful presence.
Feel free to give my office a call. We are next door in Medford, MA
www.gassonlaw.com - Disclaimer: This a general answer to your legal question. Unless you have a signed engagement letter with me, you should not consider this information to be legal advice.
As others have said, much depends on how he entered the US. If he entered with his own passport and a properly obtained visa, you may be able to file a standard adjustment of status package. If he made any misrepresentations to get a visa, or entered without inspection, you'll need to file a waiver application and he may have to obtain an immigrant visa at a consulate abroad. Since this matter deal with the unity and long term stability of your family, you really ought to consult with an immigration attorney to make sure you're following the right process and submitting appropriate evidence.
I agree with my colleagues that you should seek counsel from an immigration attorney. There is a list of criteria that can make an individual inadmissible to the U.S., and therefore, not eligible to apply for the provisional waiver. It would be difficult for you to know that on your own. Additionally, the standard for the I-601 waiver is "extreme hardship," and an attorney would most likely be better equipped to help you communicate the facts of your situation that meet that standard than you would on your own. Good luck!!