The first patch for Call of Duty 4 has been released - you can nab the 1mb-ish zip file locally from AusGamers. The fixes:

This patch addresses the issue of Rank / Stat resets reported by users moving from a Modded / Un-ranked server to a non Modded / Ranked Server. This update is not intended to revert back any previously lost rank, but to prevent the issue from happening in the future.

The forum post announcing the release also informally announces Infinity Ward's plan for updates to this popular new shooter:

"The idea is for us to do many more smaller updates more frequently. Instead of massive updates non-frequently.