I'm looking for best practices advice.

We have an team of developers enhancing our instance of Salesforce.  We're using the Scrum development methodology.

What we're struggling with is how best to include QA into our process.

Currently, sprints are VERY developer heavy and VERY QA testing back heavy.  Basically the developers lob their code changes over the wall for the qa guy to test.

This stinks for resource planning as it makes burndown charts very deceptive (lots to do at the last minute).

How are other groups incorporating QA into their sprints so that the workflow is more even?

Any advice or best practices is much appreciated!
Amber