Better question is how do I stop creating bugs in development phase?
see--> http://bit.ly/UoTa4n
If you are identifying and documenting bugs you will have to triage and fix then at some future time.
This leads to "stabilisation sprints" i.e. one whole sprint just to fix bugs. Or you can add them back to the backlog and prioritise them as part of some future sprint.
It also means that you will are providing and expect to get signed off and released software with known bugs in it (P3 & P4 aka cosmetic and minor).
This is not really agile?