If they go to the local school then the other kids will point them in the right direction. Here in the French half of Suisse every town/village has a team. My children train twice a week and play on Saturdays, first game of the season starts this Sat.
They have to register with the Suisse Football Association (a formality) to get their "Passport" which enables them to play on a team.
I find that it is really well organised here, although my boys play in the local Fribourg league we go to some tiny villages in the middle of nowhere and lo and behold there is a proper football pitch with floodlights and changing rooms it really is very well run.
The young ones up to the age of 13yrs play on 3/4 size pitches with half size goals and 9 a side, then they progress up to full size pitches.
Get them involved it really is worth it although your Saturdays will be lost forever!
Nick