What's the process? Are there classes? Fees? Do they get paid, or is it voluntary?
Edit based on comments:
I was hoping to get an overview of the process that wasn't based on any given country assuming that the ultimate goal was to eventually officiate at the highest levels, i.e., Olympics, classics, grand tours, etc. As these officials work internationally, there should be quite a number of similarities from between countries.
All of the information that you need is on this page for USA Cycling.
There are three levels for road cycling, starting with C, then B and A. C level I believe is just a clinic that you attend, pass the post test (70% minimum IIRC) and you must be 16. To move up from C to B, there are 11 modules that must be taken and passed, and then to move to Level A, there are requirements for races attended, level of races officiated, and other age requirements. The officials manuals detail these, and are located on this page.
There are different requirements for Mountain and BMX (I believe they skip the B level), and the local contacts for Missouri (If your profile location is still correct) are located on this page.
As far as fees, etc., that is going to vary from race to race and with the level of the race. I know at the races that our club puts on and a majority of the races in the region, the officials are compensated.
Contact British Cycling and ask them for information. I am sure that there will be some qualification that you will need to be an 'official', but you would also be able to get a lot of practice volunteering at smaller races. If you are a veteran racer, that would probably help, because you will have expertise.
It probably depends on your country and region. I know that in Western Pennsylvania local races and cycling associations regularly seek out volunteers to help officiate the races. For instance, here's an email to the ACA list from this March (I removed names, emails and phone numbers):
The ACA is looking for USAC Officials for our Wednesday Night racing series in 2013. XXX XXX and XXX XXX are pursuing other opportunities this season that will keep them from officiating.
Please join me in thanking XXX and XXX for their faithful services over the last several years. Their professionalism, consistency and ability to responsibly handle most any situation were a huge asset to the Allegheny Cycling Association. As is the case with many involved with the ACA, it is time for others to step up and seize the opportunity at hand.
For those of you interested, the Official's position is to essentially run the race. There are two openings available. These are paid positions ($40 bones a night!). The officials are in charge of the races. Additional detail on officials responsibilities can be found here. The commitment runs for twenty two (22) weeks starting April 10th through September 4th. It's OK to miss a night here and there as we typically have other officials that can fill in. It's a glamorous job that comes with a car allowance, paid vacation and unfettered access to ACA celebrities such as XXX XXX, XXX XXX, XXX XXX. Actually, just kidding on that sentence but I wanted to see who was still reading. If you really want to hang out with XXX, XXX or XXX we'll work on that once you're hired.
If you'd like to be considered for the Wednesday Night official position(s), please contact me directly via email at XXX@gmail.com or phone 412-XXX-XXXX.
I guess I would find out who runs the races in your region and inquire with them directly. And sign up for their mailing lists.
For this particular offer you may need to be a USAC-recognized officials, but I've seen many announcements for Wardens etc that either did not require an Official's license or included training necessary to get the license. Those requirements are just a google-click away; see http://www.usacycling.org/officials/ for fees, rulebooks and regulations, and, as an example of a training session, http://acccycling.org/news/usa-cycling-officials-clinic/
