I did a National Diploma in Aviation Environment and went straight into dispatch - didn't do me any harm. Although plenty of people do check-in before they dispatch, a knowledge of the industry, some experience (I gained this through college whilst doing my diploma) together with a burning desire to get airside can get you where you want to be. I actually made alot of contacts through college that helped, (though perhaps not essential) in getting a job.
Recruitement generally starts March with seasonal contracts ending in October - a couple of people are then kept on if there is an operational requirement, depending on their performance over their temporary contract.
And like 750 says, even if it means working in ramp or check-in briefly - you've got your foot in the door.