BDB's webchatlogger is a wonderful mod; unfortunately, it can only be used on a server. Swedix "challenged" me to write a client-side chat logger and in consequence this is what came out.
This chat logger creates HTML files, with a similar format to webchatlog v 2.2. As levels change, new logs are opened. However, there are some differences, such as coloring different message types, rather than saying the type. Color key is as follows (I was too lazy to make this customizable :p):
-Green: A message sent to all players (with the say command)
-Light Blue: A message sent to all teammates (with the teamsay command)
-Red: A message indicating someone died (known as a deathmessage)
-Brownish red: A message that has to do with a kill. This includes headshots, first bloods, killing sprees, and multikills.
-Purple: A "pickup" message. These messages inform the user that he picked up something (weapon, ammo, inventory, etc.)
-Black: Any other event that does not fit the above catagories (flag capture, player joins/exits, etc.)
Note that you may configure which of the above message types are logged or not. Time messages, "you killed x", and "you were killed by x" messages are never logged. Also never logged are "console" type messages, such as "unrecognized command".
The player name column in the HTM file is filled for say and teamsay messages. The name is the same color as the players team (white for spectators and in deathmatch games).
Another advantage of a client-side chat logger is that it enables you to take chat logs of demos.
A message summary was long requested with Unreal Tournament Demo Manager. While it would be hard to pull it straight off the demo file, it should be quite easy to simply run through the demo file with chat logger enabled, which will generate a log from the demo. (which would be identical to a log taken in the real game).