The official Premier League fantasy football site had 2.7 million participants last season and it is very, very easy to play.
I have created a league called Epsom & Ewell FC and it's easy to enter, all you have to do to join is visit the site here.
Then enter a team. Just using auto-complete for now is best, as it gets you up and running for now and unlimited transfers are available before the season starts on 18th August. Your first deadline is about 11.00 on that morning but I recommend that you do it the night before at the latest as the site gets very busy near the first deadline.
Once you have a team you can enter private leagues. Just go to the league tab and enter the league code which is below.
It's easy to do but if you have any questions, just add a comment below and I'll get back to you.
If you reckon you know about football, then come and have a go.