I cut my theory teeth on
C-Theory. This was around 1999, they are probably seen as less relevant now but honestly, they still seem cutting-edge to me. There are worse places to start.
And I don't want to contradict what everyone else is advising (I'm new here, not looking to cause trouble!), but I think it's easier to start with secondary sources, get a general survey of the landscape, a thumbnail concept of what Hegel's about, what Lacan's about, etc. before diving headfirst into the source material. I would even recommend Zizek, because I see him as a secondary source, and he covers practically everyone (especially Hegel, Lacan, and Kant). If you're interested in postmodern theory specifically, then
Panic Encyclopedia might be the best introduction. Those essays give you a great 'feel' for the postmodern perspective: it's essentially an inventory of all the postmodern rhetorical/aesthetic/thematic motifs.
Hope this helps, and good luck.
EDIT: and yeah I'm the lone remaining Arthur Kroker fan/protege. I see nothing wrong with theorists advertising themselves as rock stars, I have no problem with that.