How can you perform a search using content types.
For example, I want to search for all documents having content type "ct1" and where the field "fld1" contains the word "finance"?
Is this functionality doable out-of the box?
This is available via the advanced search web part (you add constraints by modifying an XML-based property.
You will need to create a Managed Property for content types as this isn't available out of the box. You'll also need one to match your "fld1" field. Once this is done, you can then add the Managed Proeprties into the advanced search web part XML.