They have a working group to develop a common format for IDS alerts. The group has worked through the requirements phase, and the design is substantially fleshed out, though details continue to change. Preliminary implementation work is probably possible, though implementations would have to change as the standard is finalized. The design involves sending XML based alerts over an HTTP like communications format. A lot of attention has been paid to the needs of IDS analysis, and to making the protocol work through firewalls in a straightforward way.
More contributors are always welcome.
IETF working groups are open to any technically competent individual who wishes to contribute. Individuals represent their own views on the best way to solve the problem, rather than the agenda of their employer. There is also an effort by the ISO's T4 committee to develop an Intrusion Detection Framework. The status of that effort is presently unknown, and attempts by the FAQ item author to reach prominent figures in that effort were unsuccessful. CIDF development is presently dormant.