I just bottled a brew I made with frozen raspberries. I added the raspberries to the secondary (they were frozen bags of organic berried purchased from Whole Paycheck, er, Whole Foods). Boiled them first, both to ensure sanitation and to further break down the cellular structure. The good news - the great news - is that a LOT of the flavor and aroma has been maintained after three (or maybe four, I lose track) weeks in the secondary. I had also added some Grade B maple syrup, also brought to ~ 180 degrees or so for ten minutes, which I can't directly taste but might be contributing to the brew's nice body. So far, I love this beer, I wish I made more - right now, it's almost like a desert beer.
But, what I would recommend, and what I would have done if I hadn't left the beer in the secondary so long already, is a week or so in a tertiary (spelling?) fermenter. Lots of trub, lots of floating bits of raspberries that were tough to keep out of the bottles. I ended up skimming some off the top of the surface in the bottling bucket with a sanitized spoon.