Unfortunately I don't know any such sites. But I'll explain what I can. I might have been misleading when I mentioned Photoshop's script. I meant what in Photoshop are called actions and they aren't that hard to create and use. Open one of the images you wish to manipulate.

1. Open Actions-panel from Window-menu.
2. Create a new set of actions for your own scripts by pressing the black arrow in the right corner of the Actions-panel and choosing New set....
3. Name your set of actions (e.g. 'my actions') and press OK.
4. Create a new action by pressing the black arrow in the upper right corner of the Actions-panel again and this time choosing New action....
5. Name your action with any name you wish(e.g. 'alpha cut') and press OK
6. Now you can notice that the button(Record-button) in the lower margin of the actions-panel with a red circle in it is pressed down and activated.
7. You can now do the picture the modifications you wish Photoshop to perform for all the images in the sequence. I cannot remember if drawing tool apply but filters and image adjustments and such will certainly be recorded to the script.
8. For example if you wanted to cut the alpha channel from the background you would do the following: 1. double click the background so it becomes a layer instead of being a background.(This enables the cut with the alpha channel)
9. Create a selection of the Alpha channel (Carrara creates a Mask-channel) by Command-clicking the channel or by choosing Load selection... from Select-menu.
10. Inverse the selection to cut the background instead of the objects
11. Make a cut with the selection by pressing Command+X or choosing Cut from the Edit-menu.
12. Save the file into a different format by selecting Save as... from the File-menu.
13. Press stop from the Actions-panel.
14. Your action is now ready.I recommend you to save your action from the black arrow in the upper right corner of the Actions-panel.

You can now apply it to all the images in your sequence. 1. Go to File, Automate and batch....

2. In the Batch...-window select your set to the Set and your action to the Action.
3. Choose the folder your sequence is in by pressing Choose... in the Source-section of the window.
4. The Destination-section you unfortunately have to test because I haven't quite figured it out yet. I have gotten it to work but somehow but I still don't know what I have done. Probably the best option is to choose Folder to the Destination so the files are saved in to another forlder. Then press Choose... to select the folder.
5. I think that if the Override Action Save AsCommands is activated Photoshop saves only with the Save as...-command set in to the Action and not automatically after completing the Action. So you should probably activate it.
6. In the file naming-section you can alter the file name of the new created file.

Last time I tested creating a sequence of pngs with batch , Photoshop insisted on putting copy to the end of each file's name. I don't know if Flash recognizes sequence numbers if they are in the middle of the filename but I think think this might be a problem. That time I had only 24 frames so I manually changed the names but if there are more files it would be frustrating to change all their names. It might be possible to create a new batch that opens the pngs and saves them with a different name. After all there are the sequencial numbers in the filenames that Photoshop will recognize and do the batching it that order.
I hope this helps you atleast a bit. -Hannu Kulju