basically you need
1 - something that enqueues requests
2 - something that reads the queue and processes the requests.
1) to enqueue request you can make a WCF service, so you can have a "client" that sumbit request using that service.
2) to read the queue you can create a ServiceHost that keep waiting new requests on the given queue.
BUT keep in mind that is a "Fire and forget" approach, so when you put something in the queue you can't know anything about it.
if you need to get informed about your request's status you need a bidirectional system with 2 queue and things become a little more complex.
you can find a working sample here
Creating a WCF Service with MSMQ Communication and Certificate Security[
^]
or here
wcf-and-msmq-part-1/[
^]
bye