Ahhh...got it.
Code:
INSERT INTO VotingSite (userid, VotingSiteType, active)
SELECT ID, 10, 0 FROM userinfo
See that? You can SELECT both fields *AND CONSTANT VALUES* from a table, so combine that with INSERT INTO and you are done.
NOTE: Don't put apostrophes around numeric values ('10' in your example) unless the data type in question really is a string type.