A: Mike McArtor, copyeditor for DailyMTG:
As you might imagine, this question comes up pretty frequently. A lot of players of our games (not just Magic, but also D&D and Kaijudo) imagine that Wizards of the Coast is an awesome place to work. Just between you and me, though—yeah, it totally is. ;)
But to truly answer your question, let me provide you some links!
Wizards of the Coast Careers Page
— What better place to start than here? This page shows all the current openings we have in the company. (Protip: Just about every job here requires a four-year degree from a university, so you'll need to get one of those!)
Hasbro Careers Twitter
— If you've got a Twitter account (and if you're a Magic fan you really should!) and you want to work at Wizards (which you obviously do!), you can keep abreast of new job openings here. This Twitter account talks about job openings from across all of Hasbro, which includes us.
"How To Get Your Dream Job"
— Here, Magic Lead Designer Mark Rosewater talks about landing your dream job. In fact, Mark frequently posts links to job openings in his articles, so if you're not already reading him weekly you might want to start!
"Getting a Job at Wizards"
— Finally, Senior Designer Doug Beyer pretty explicitly answers your question in this article. (I mean, just look at that title!)
Good luck! :)