is it possible to make some colors from image transparent in *.jpg format? ???
Yeah, I use photoshop which makes that very easy. You might want to consider using PNG format though. JPG is a lossy format which can make you graphics look bad when you save them.
I have tried that when I used *png images in java the transparent ares weren’t transparent. I mean that can i modify the image with java making some colors to blend in the background for a while. :-/
A little OT: Does anyone know how to save a png with alpha channel with Photoshop 7.0? Seems to me this option is gone… I’m stuck with PS 5.0 because I can’t find any functionality for png alpha channels in 6.0 and 7.0 ??? ???
I don’t know about Photoshop, but I use GIMP for this all the time. Saving an image that has transparency to PNG “just works”
Macromedia fireworks 
it’s native file format is PNG
(or png compatible as it saves extra layer data so you can edit it, but exporting to png makes it true png)
[quote]A little OT: Does anyone know how to save a png with alpha channel with Photoshop 7.0? Seems to me this option is gone… I’m stuck with PS 5.0 because I can’t find any functionality for png alpha channels in 6.0 and 7.0 ??? ???
[/quote]
Try “Save for Web”.