About two years ago, I posted a video showing how to use SQL Replication with HADR. Lately, I've gotten a bunch of requests to do something similar for Q Replication and HADR. The good news is that I don't have to :) there's now a white paper called Using Q Replication with HADR on IBM's developerWorks. It provides very clear information about best practices, considerations, etc.. I've got a few highlights here.
If you need a picture to help visualize how these fit together, here's one and there are more in the white paper:
I also see two areas I think could use a little more detail:
Why Use Both Q Replication and HADR?
You can see the answer in the picture above. A company uses Q Replication to provide continuous availability, Active-Active Databases, or Dual Warehouses across multiple sites. They then use HADR to provide a local HA or DR solution for one or more of the active sites.
If those both sound like the same thing to you :) see the post titled DR, HA, and Continuous Availability - What's the Difference?