I'm a lifelong hobbyist hacker, who'd like to become a paid, professional programmer,
I first cut my chops on QBasic, on a 386, at a tender age, but I've never programmed in a professional capacity, have no professional certifications, and got a liberal arts B.A. I'd say (in all modesty) that I have a expert level understanding of UNIX programming, kernel internals, and memory management, and an intermediate to advanced understanding of algorithms/data structures. That is, I've read Knuth, but get stumped on a lot of the harder problem sets. I can hack in x86 asm, C/ObjC, Python, Perl, etc., though I have little C++, C# or Java experience. I've worked plenty in IT, both before and after college, but only in Network Security and System Administration type fields, where programming abilities were a plus, but not the core competency required.
Programming job openings seem intimidating--my resume just doesn't fit within their categories, and I really have nothing to prove to them that I can code. I feel like I would come off as competent in an interview, but not in a cover letter. Any advice about making the leap from hobbyist to the 'real time'?