IWBC is 8 weeks at CID Corry Station in Pensacola.
See the Program Authorizations for special requirements:
Active
Reserve
Technical degrees are preferred, but not required. IDC accessions as a whole are running about a 60/40 split of technical to liberal arts/social sciences degrees.
If you are going Active, you will do OCS.
If you are interested in the Reserve side right away, all reserve accessions happen via the Direct Commission Officer (DCO) program, even for prior service. Graduate degrees are preferred, and the boards are very competitive. They are also looking for people with significant leadership experience (e.g., management/leadership experience in civilian work, volunteer activities, etc.), and typically people who have civilian jobs which are related to this field.
Once you are commissioned, you will complete IWBC, your IW quals, and general quals for the IDC as a whole. Your first duty station is likely to be one of the "big four" NIOCs (MD, TX, GA, HI), colocated with NSA/CSS. This and other general info is
available here. If you are a reserve officer, you might also be assigned to one of many smaller NIOCs, each of which work for one of the big four.
Take a look at some of the resources in my sig, and good luck.