If I am using DD4T or MVC framework, what are the options integrating smarttarget? Obviously we won't to be able to use the TBBs.
There's no reason why you still can't use the TBB's. I'd recommend using them in the event you wish to move away from the DD4T mvc framework in the future.
Simply output your content as REL and transform the TCDL tags yourself when you return your content from the broker.
You can also query Fredhopper directly via the query web service -passing the various facets you wish to query on.
Fredhopper will return results that contains several components such as a breadcrumb, facetmap, item lister and promotions.
You can then render these as you wish.
You can output the TCDL tags yourself which the Deployer transforms to your site's target language or render the target language tags in your template directly.