How can I help him get his US citizenship and do I still have to fill out the I130 even though he has a visa?

Generally, a foreign national who is married to a U.S. citizen, and who has entered the U.S. lawfully and with inspection (with a visa), will be able to succeed in a marriage-based adjustment of status application to become a Permanent Resident (to get a "Green Card"). After being a Permanent Resident for three years, the foreign national then may apply to become a naturalized U.S. citizen. It is not possible to skip the Form I-130 and I-485 application steps and go directly from having a nonimmigrant visa to an applicant for naturalization. There are many issues and considerations to determining whether a foreign national married to a U.S. citizen will be eligible for these types of applications, and it would be wise for you and your husband to consult with an immigration attorney. After learning all of the relevant information about your husband, his immigration-related history, your marriage, etc., an immigration attorney would be able to advise about eligibilities, options and strategies, and would be able to offer legal representation in the often quite complex application process.

Yes, you still need to file I 130 if you never did that and his visa is not an IR or CR.