The colour blocker module (not color blocker -- we're English) will prevent mIRC-style colour codes showing on a channel. When a line containing colours is sent from a client to the channel the whole line will be rejected and a numeric sent to the offending user.
Configuration Tags
None
Additional Modes
None
Additional Commands
None
Special Notes
The actual numeric sent when messages are blocked is the numeric 404. This is the same numeric used for 'Cannot send to this channel' although the string is different so many clients will display it correctly, the ones that do not will still react in an appropriate manner.