My own personal exposure to category theory mostly consists of reading the following blog entries:

- The entire beginning of <a href="http://unapologetic.wordpress.com/">The Unapologetic Mathematician</a>,
- Todd Trimble's <a href="http://topologicalmusings.wordpress.com/2008/06/22/basic-category-theory-i/">series on basic category theory</a>,
- Random weeks of John Baez's <a href="http://math.ucr.edu/home/baez/TWF.html">This Week's Finds</a> (unfortunately it is somewhat hard to search these).

I won't claim that this is at all a systematic or comprehensive way to learn category theory, but I do think there's some genuinely good writing here and that it's gotten me comfortable with category-theoretic language, even if I wouldn't actually say that I "know" category theory (whatever that means).