Question: I've got a Windows 2003 Active Directory infrastructure, and there are times (such as when terminating an employee) that I want instantaneous propagation across both of my AD servers. Currently, I make the change in both places, which I suspect is unhealthy, but it's the only way I know to make sure that the account is disabled to every machine. 

Is there a better way? Do I have to wait for the normal propagation time for convergence, or is there a way to "force" it?

Answer: 
If you go into Active Directory Sites and Services, you can force replications. Open the Server object and click on the NTDS Settings. This will give you a list of their replication partners for GC data as well as regular DC-DC traffic. As I understand it, you can force replication by going to each of the connections, right-clicking on it, and choosing "Replicate Now".
[![alt text](https://i.stack.imgur.com/kuvC4.png)](https://i.stack.imgur.com/kuvC4.png)  

(source: [sysadmin1138.net](http://sysadmin1138.net/images/replicate-now.png))
There is an even easier change. Just reset the users password. That is one of the few instant replications that AD performs. No need to run site replication

EDIT:

Small edit. It's not completely instant. What is does is forward the change in an out-of-band update. (It doesn't wait for normal replication cycles)

however, it's probably about as close to instant that you can get with AD.