IS JPEG and TIFF support going to be added? Cause all my textures are in JPEG and TIFF format. :-()
Well, it isn’t there yet, and they haven’t said whether it’s going to be. But a lot of people have requested this, so my guess is they’ll put it in the next version, or the one after. 
I had the same thought/question when I first starting using Z.
Now, 9 months later, I don’t particularly care if it ever happens. I just converted my old files to Bmp. And create all my new ones as bmp or psd. shrug
To be honest I don’t miss the feature anymore. I primarily use .psd, .bmp (and convert to jpeg for web presentation)
My print gigs require .psd or .AI or .eps.
I haven’t had a request for TIFF in a few years.
This probably doesn’t answer your question persay, but I felt it important to say, I felt your pain/need. But I haven’t had any problems with the difference.
I must also second Muvlo’s statment about Pixologic’s awareness of the enduser.
You will NOT find another software supported by a company this in tune with their customer base. No doubt, these formats will one day be available. 
you can Convert the Hole Batch in seconds using this http://www.acdsystems.com/English/Products/ImagingProducts/Utilities/Picaview/index.htm
It was my biggest sofware wish for 2001. JPG support is needed to help keep alpha/texture/exported image files down but also to keep ZScript images small.
I’m wishing like mad right now…
Glen