All depends what connection type you got :D
Check out QUESTION #1 in the following post, especially the note to server admins:
In case that link doesn't work, here's the excerpt:
If you are a CoD server admin, go to www.punksbusted.com and read the "Settings Support" section for tuning punkbuster. For example, several server admins have reported that they reduced lag for their users by changing their pb_sv_CvarWalk server variable to something like 2 (or even 0 to disable); turning off screenshots helped too.