As I see there isn't any leagues for us this year yet, this could be the one where one and all decent to pit your wits against your fellow forum mates.
I have used the http://f1manager.info/
one for a while now and find it the best one out there that's still running. The F1 Manager log in is as below:
League Name: F1 Technical League
I know there are people in here who use that one as there's 32 members as I am the admin for the league.
Hope this is in the right area, the mods can shift it to the area they want to if they want.