Hello Guys, i want to know how to create transperent images using Photo Shop.

I tried to get this in Google search,but i failed.

My Avatar Should look Transperent in various websites.

without making any changes it should mix up with various other sites background

Please do this Help for me.

Also provide me an Avatar like this which is provided below link ,not exactly this but different which should have a look of a Moderator or Administrator.
 
http://i264.photobucket.com/albums/ii165/v.../untitled-1.png.

Note: The maximum size of my Avatar should  150 be 150 pixels or 39.1 KB

Also provide me a Good Signature with an name in it (Vamsi Krishnam Raju) and(RDX) ,the sig should be of black background and it should be transperent.

Note: The maximum size of my Signature should be  500 by 100 pixels or 19.5 KB

If you want to create something with a transparent background, that is pretty easy to do. Whenever you start a document in Photoshop, you have to enter several settings, such as the dimensions of the canvas. Here you can also edit the background color, you just have to set the background color to transparent and you are done!

If you have a background layer in your PS file, it is usually completely white. Just delete it to get a transparent image.