Co. Leitrim Civil Parishes Map
Co. Leitrim Roman Catholic Parishes Map
Co. Leitrim GENUKI
Co. Leitrim IGP
Leitrim Genealogy Centre (RootsIreland)
Leitrim County Library - Local Studies
Special Ingredients - Record Finding Aids
Co. Leitrim Church of Ireland Parish Records Finder
Co. Leitrim Registry of Deeds Townland Indexes Timeline
The county archive service appears to be just getting off the ground, so I have substituted a link to Local Studies in the Leitrim County Library.
I also came across an online database of Co. Leitrim cemetery records. No idea how far the records go back, but you might get lucky.