callbacks between client and server applications - help!!!

we're busy working on a 3-tier client/server app. the client app is the
form of a activex component in a web browser. now we are looking for a way
so that, when changes occur on our database (inserts deletes etc), the
appserver should pick up this changes and send some kind of message to the
client, or fire a procedure/method on the client. we are using a socket
MIDAS connection, fully licensed.
does anyone out there have any pointers / references for us. any help
please reply by email too

elrick du toit