QUOTE(nimble @ Jun 22 2007, 02:24 PM)

This is a difficult one. Most people from India seem to get rejected for a visitor visa when an immigrant visa is pending. The basis is that you are unable to prove strong ties and reason to come back to India. However, if you are able to prove that, there is no harm trying at all. It should not affect your immigrant visa petition regardless of the decision made by the consular officer.
Surely, it won't affect her immigrant visa petition, but her tourist visa application will likely be denied because the Embassy will be affected by the fact she will have her immigrant visa interview soon. So there is no point for wasting time.