How do I sell myself in a short email (that I hope will lead to a job interview)?

I found a listing for a job that I have a lot of experience with (IT-related stuff). The listing asks applicants to email them with a brief description of themselves and relevant work experience. What should a “brief description of myself” include? Do I attach a copy of my resume or is that being too presumptuous? What can I say in short space that will make them want to ask me for my resume/come in for an interview?

I’m over-thinking this a bit because I’ve been out of work for years (it’s a long story) so I need a job pretty desperately. I fit the job description almost perfectly, plus I love the company and would love the chance to work there. But I’ve had a lot of bad luck with my past email inquiries. Maybe I was too plain or boring in the past? I usually aim for plainness and clarity.