Kim Harrison has written "'Twas the Night of the Solstice" for the Eos blog.

Susan Palwick has been posting sonnets on her blog recently, about hospitals and chaplaincy.

Tom Disch has been writing a lot of poetry on his LiveJournal, but I don't recall anything particularly festive.

Update: More! More! More!

Lynn Flewelling on Christmas in SoCal.

Jennifer Fallon's version of "'Twas the night before Christmas"

Endicott Redux's "Sunday Poem" has a Christmas connection this week. 

Update 2:

Alma Alexander provides yet another rewrite of the Clement Moore favorite, this time with a cat theme. (I'm not knocking the idea of fitting "'Twas the Night..." with new words; when my second son was born December 27 of 2000 I wrote a pretty bad version myself.)

Sherwood Smith posts a G.K. Chesterton Xmas poem.