We thought it was worth passing along. (Shared with Julie's permission.)
1) duotrope.com (annual fee optional for best functionality) - searchable data repository with links to publishing sources and literary agents, lots of stats, interviews with editors, submission tracker for your work.
(2) Submittable.com (free to use) - widely used submission tool, but under the "Discover" heading lists lots of calls for submissions, contests, etc. Only tracks submissions done through this platform.
(3) Newpages.com (free) - includes info for calls for submissions, contests, workshops, conferences, and more.
I check all three of these sites for opportunities to submit, and track my submissions on Duotrope and/or Submittable. Beats handwritten sheets! :-)