I don't know of any OS X utilities that'll automatically convert .MOV files to animated gifs and optimize them for the web. But this is how i do things manually...
1) just use QuickTime PRO
to copy all the desired frames (one by one)
2) paste the desired frames into new -individual- Photoshop windows (don't save them yet)
3) for each frame that was pasted in Photoshop, reduce the Color Table to 256 colors for -every- Photoshop window
4) save every color-reduced frame in Photoshop as a .GIF file in a 'new folder' on your desktop or wherever you prefer to save them (this folder can be deleted after producing the final animated gif)
5) go into GraphicConverter and select the 'Batch' function/menu
6) select the folder where you saved all the individual frames (select all the frames) and create a 'Super Palette' for them (you can also save the created palette in the same folder)
7) open GifBuilder
and enlarge/reduce the 'Frames' window if you need to (you'll be dragging and dropping frames from the Finder into GifBuilder)
8) in the Finder, go to the folder where you saved all the .Gifs and select all the frames (but not the palette file)
9) drag all the frames into the 'Frames' window in GifBuilder
10) in GifBuilder, make sure the frames are in the right order by clicking and dragging them into place
11) Select all the frames and go to the 'Options' menu
12) select 'Colors' and chose 'Custom Palette...' or 'Load Palette...' (it's been a while, so i can't really recall what it was called)
13) load the palette you saved in the folder
14) depending on wether you want your animated gif to loop, go back to the 'Options' menu and select 'Loop Forever'
15) save your final animated .GIF (preferably on the desktop)
Note: You can bypass the step that requires GraphicConverter by pasting all the individual frames from Quicktime, -ALL- into a single and LARGE Photoshop window, and then use Photoshop itself to create a 256-color pallete for use in GifBuilder. However, this requires that you have an insane amount of free RAM and scratch hard disk space to work with.
(EDIT: Clearly, i'm no professional computer graphics artist, but this method never failed me. But yeah, if you have Flash, that'd be a far better option...probably a hell of a lot less time consuming as well...)