It means good news. I assume that you had filed a I-130 petition and your notice says that it was approved.
Next step is Adjustment of Status, if your husband is in the US. Unless you already filed it, you need to file the full I-485 package to adjust his status. Good luck!
This answer should be clarified as I expect that the attorney probably meant to do. If you are a U.S. Citizen and your husband has been lawfully admitted into the U.S., then he may be eligible to adjust status. That is, to file in the U.S. for his permanent resident status (or green card) in the U.S. It is wise to double check whether he is eligible. Some visa holders may be ineligible or inadmissible.
If your is outside of the U.S., then you should be receiving additional documents from the U.S. State Department's National Visa Center. It will inform you of the additional filing fees, forms and documents that it must receive to begin visa processing outside the country. This can take quite a bit of time, so you want to try to get the forms and documentation filed correctly on the first try. It is not uncommon for the National Visa Center to reject some of the forms and ask for additional documents.
For these reasons, consider discussing this matter with an experienced immigration attorney. An experienced lawyer should be able to assist with providing advice and with processing. The American Immigration Lawyers Association provides the names of competent attorneys in immigration. You may also consider the reviews of attorneys on this website, as well.
Assuming the approval notice is for an I-130 and that you are a U.S. citizen, your husband is now the beneficiary of an visa petition. Your fact pattern does not provide sufficient information to determine if you husband is eligible to adjust status here in the U.S., or if he will need to leave and consular process. Retain an experienced immigration attorney before you spend any money in a course of conduct with USCIS.