[Linux-disciples] apache question

[Jamie Forrest]

How would one set up an Apache rule that redirected a request from one  
domain to another domain, without showing a different address to the  
client in his browser?

For example, let's say I have an application set up at  
myapp.domain.com. I want www.domain.com/myapp to redirect to  
myapp.domain.com, but still appear in the client's browser as www.domain.com/myapp?

I don't need the specific syntax of the rule, just the general idea.  
Thanks!
Jamie