football is pretty well organised here. Here's a link to the tables http://www.football.ch/fvnws/de/meis...n=15304&s=2012
Concordia Basel and Old boys are traditionally the 2 biggest youth teams in Basel apart from FC Basel. Your son would be in the B-Junioren age group.Concordia and Basel have U-16 teams which plays against the the youth teams of other professional clubs. As Basel is the hotspot for Swiss football both teams are leading their groups
There's normally trials for them periodically but as you see to get in he'd need to be among the best goalies in Switzerland.
The coca-cola league is of a very high standard as well though. You can have a look through the tables and see what's near you and at what level he wants to play at and check it out with the clubs. Normally he could go by and they'll have a look at him. Some teams may have waiting lists it probably depends. Obviously the better the team the hard the competition. Especially as communication is generally pretty important for a goalie. The season is nearly over now anyway. The season starts in August with training starting in July.
Anyway the league hierarchy for B Junioren is the u-16s, coca-cola league then promotion and then 1. Stärkeklasse