Photoshop Saving As PDF When I Don't Want It

Hello,
This is probably very obvious but can't work it out.

Have recently got CS3, was working on ID earlier and exported my document as a PDF (this might be relevant).

Then started work on a photshop image, went to save it as a photoshop file, when I did it said my adobe PDF preset might over ride this, and it saved it as a PDF isntead.

Can't work out how to stop it doing this. I have photoshop format selected when I go to save, not PDF?

HELP!

Thanks,

E