UCLICK.com provides daily puzzles to many newspapers and magazines. You can access ALL of UCLICK's puzzles (dating back to 2005) in XML and text format at:
generic: http://www.uclick.com/puzzles/sudoc/data/sudoc[yymmdd].xml
Newsweek/Washington Post: http://www.uclick.com/puzzles/nwdoc/data/nwdoc[yymmdd].xml
Woman's Day: http://www.uclick.com/puzzles/wddoc/data/wddoc[yymmdd].xml
USA Today: http://picayune.uclick.com/comics/ussud/data/ussud[yymmdd].xml
and their 16x16 puzzles:
generic: http://www.uclick.com/puzzles/sudom/data/sudom[yymmdd].xml
Newsweek/Washington Post: http://www.uclick.com/puzzles/nwdom/data/nwdom[yymmdd].xml
Woman's Day: http://www.uclick.com/puzzles/wddom/data/wddom[yymmdd].xml
and their Sudoku-X puzzles:
generic: http://www.uclick.com/puzzles/sudninex/data/sudninex[yymmdd].xml
Note: Woman's Day puzzles before 1 Mar 07 are duplicates of the generic puzzles. Many other newspaper Web sites subscribe to the generic set, as well.