Well it might sound a little silly for those who are experienced with Photoshop but i'm learning and i need some help about making a color transparent...For example i have an image in black and white and want to make all the white transparent and keep the black, how can i do this? :( Thanks for your help and your time :)

quick easy way is to change the layers blend mode to "multiply".

one thing to keep in mine, it can not be the background layer. if it is either "duplicate" it or "double-click" on the Background layer to make it an editable layer...

any trouble just shout!

:)
retrocity

I whould do it this way: duplicate layer, select all the whites -- rather by Select-Color Range or, for more accurate work, by Lasso (but I am a lassomaniac). Than I whould hit the Ctrl-X combination and cut the selection of... voila! Happy learning -- I enjoy every minute I spend in Photoshop! :-)

Thanks for helping me out but i forgot to mention that i'm trying to cut all the white from a template for Poser and this cannot be done with the lasso...sorry, i should have told what this is all about. Again thank u Retrocity and Serious :)

Another 3 free filters that are good to have can be found @ Eliminate It!.
Eliminate White, Eliminate Black and Red Prince Whitewash come in very handy.

Thank you so much! Whith "Elimanate it" i eliminate the white in a second! Now i can go on to the next step... :)

Control-clicking on the CHANNEL wil select all the white too, and the half-white half! You use the channel as an alpha channel. This might help if you have too much of a white halo. If it cuts away too much you can multiply your LAYER with a copy of itself. Just keep this in mind when you bounce into problems. I do not think you will, because if you set your Poser template layer to 'multiply' halos are nowhere to be seen.