The 2013-14 league entry for cyclocross in the eastern region was opened on August 15, and is administered on the BC website: Eastern Cyclo-Cross Association - Profile. If you have any questions then you need to email EasternCycloCross@gmail.com.
Late July is an important date for your diary, if you want to enter the Eastern region cyclocross league. By signing up early you will make the organiser happy and you won't run the risk of your first race not counting for league points. Go to the Eastern Cross website's Joining the League page (refresh the page if you've visited it in the last week or so), and check whether you're able to sign up.
Don't forget the BC side of things, too. They have a page called Events for series: Eastern Cyclo-Cross League where you can mark each event as a favourite in your race calendar.
In the meantime, why not browse the events for 2013-14 and familiarise yourself with the event locations: