Halo 3: Parasitic-Talking-Flood-thing

As you all know, in Halo 2 there was that Parasitic-Flood-Thing. Is it going to be in Halo 3? If so, what does it have to do with the storyline? I mean at the end of Halo 2, you see it slowly crawling towards the hologram (can't remember her name) and then the game ends. I'm curious about this.

Cortana seems to be part of the flood now.

I seriously hope that is a good excuse to give those bastards some AI. Some mutated hunters would be cool too. Oh and do make them raggdolls this time. I hate pre-animated deaths!

Off course the flood returns, you find out in Halo 1 that Halo's are built to contain the spreading of the Flood...