OMG! I found a link for you.

Okay So you want to know how to make the icky white backgrounds transparent right. well I have good news!. I have a link to a place where you can Download a Free Program to make the background transparent!

Click Here to Download Giffy

Here I will walk you through how to make things transparent.

Okay So you have a sprite with a nasty white background right.

Ie: (Posted Image) <see nasty white background!

Save the Img as 24 bit Bitmap <YOU Must do this.
Once you have saved as BMP go into a paint program. Then OPEN. But DO NOT open the sprite. Right click on the sprite and there should be a some new Options. Click OPEN WITH GIFFY. and it will bring up a grey box. And the sprite should be there. white background and all.

Next step Make sure to click the box Transparent. and it should show a white box. (make sure you change the color in your paint program to make the background a color not used in the sprite. IE. Lime green.

(Posted Image)

Now Open with giffy and Click the Transparent box. if it still shows as white but you have the lime green background hover over the sprite and there will be a cross. Put the cross on the lime green and click. The box should change to green. Then Save as GIF and Upload to an image host. IE: Photobucket and It should look like this after you are done.

(Posted Image)

Cute no ^.^ Congradulations. you have just made a Sprite with a Transparent Background!!!!