I took my bike on Cheesyjet at the end of last year. You have to be careful that they don't try and sting you for excess baggage as your extra bike fee should mean they won't charge you for any excess. The check-in staff in the UK understood this but the Spanish ones were awkward about it.

Re packaging, take off your wheels, handlebars, rear mech and possibly the mech hanger. Apparently brake discs can sometimes get tweaked but I left mine on and they were fine. I got a bike box from outside Halford's, cut it to size and then put this inside the bike bag, then taped pipe lagging over the chainstays, fork legs and dropouts and it seemed to work fine. Good luck!

Good news about Easyjet changing their policy. If you have disc brakes don't forget to pack the space between your disc pads with hardboard or something similar, and tape it in place so it doesn't fall out! I always remove the rear mech and zip tie it to the frame. If you have an old knackered rear hub, put that in place to keep the rear end from collapsing under the weight of any baggage that gets put on top of your bike bag. My friends Cannondale Jekyll was a write off after travelling Easyjet to Nice as the swing arm had been completely compressed. If you have wide handlebars you may need to remove them from the stem and tape them to the frame.