Belgium has two population groups that did not always share the same history. These groups also speak different languages. The Flemish live in the Northern and Western half of the country. They speak a dialect of Dutch, called Flemish. Flemish and Dutch are like British English and American English. They are one and the same language, pronounced differently and using different words for some situations.
The Southern and Eastern part of Belgium is called Wallonia. The Walloons speak French, albeit with a distinct dialect that is in many ways similar to that of Alsace region. In the far Eastern part of Belgium, there are two German speaking communities that were annexed after World War I (Eupen-Malmedy) and have remained part of the country since. Because of that Belgium is tri-lingual with three official languages: Dutch, French and German.
The capital of Belgium is Brussels and it lies well within the Flemish region. Even so, most people in Brussels speak French and Brussels often aligns itself with the French speaking region of Wallonia. Technically Brussels is bi-lingual but often the capital (and other regions) chooses English to avoid the hassle of using two languages or appearing to favor one over the other --with all the associated political issues.
Recently, Belgium has become a federal state with three semi-autonomous regions. The regions are Flanders (Vlaanderen), Wallonia, and Brussels. No, the German community is not semi-autonomous.
Cycling in Belgium is controlled by the Koninklijke Belgische Wielrijdersbond (K.B.W.B.) aka the Royale Ligue Velocipedique Belge (R.L.V.B.), a non-profit organization. To avoid confusion or partisan politics the website is at www.belgiancycling.be. KBWB is a member of the UCI, the UEC and the BOIC. KBWB is where you want to be for forms. Fortunately, most of the information here is in English and the relevant personnel is fluent in English. KBWB is located in the Brussels suburb of Vorst/Forest.
KBWB has two daughter organizations, called Wielerbond Vlaanderen (WBV) and Federation Cycliste Wallonie-Bruxelles (FCWB). Both have websites with calendars that list competitions and results. Even a cursory look at both sites and their calendars will convince anyone that all the action is in Flanders.
WBV has recently revamped its website, http://new.wiebovlaanderen.be/. The older site, www.wielerbondvlaanderen.be is still around and has some very useful features that are absent at the newer site. The relevant info on the WBV website is under competitie (competition).
Racing in Flanders has several disciplines: road (weg), track (piste or baan), cyclocross, mountainbike, bmx, and indoor, which includes such things as cyclo-bal (cycle dance) and kunstwielrijden (or artistic cycling).
By and large Belgian and Flemish cycling follow UCI rules. The rulebooks are on the website and comprise several chapters, but unfortunately English versions are not available. One thing to note is that USA cycling -for the most part- is organized quite differently and does not adhere to UCI rules.
There is no equivalent to racing categories ("cat racing" as it is affectionately called) in Belgium. Furthermore, youths are only allowed to race with their age-grouped peers. They cannot enter (the non-existent) "Cat" races or race with adults.
While everyone ages 10-18 is called a "junior" in the US, UCI rules stipulate that juniors are 17-18 yr olds. Other age groups have different designations (and rules). The youngest UCI group is the junior group. All racing prior to age 18 is governed by local rules. To race in Belgium as a foreigner you need to be 15 years or older.
18 yrs and younger groups have restrictions with respect to how often they can race, how far they can race, and what type of gears they can use to race.
In Belgium the following labels apply:
8-11 yrs miniemen
15-16 nieuwelingen (novices)
19-23 beloften/espoirs (sometimes also called U23)
23 and up Elite, except that anyone 19 and older with a pro contract is also an Elite.
Elite z/c (zonder contract) are amateurs.
All ages listed are "racing age," i.e. the age your reach on Dec 31. of the calendar year.