If you have the icon file, you shouldn't have to worry about Paint. Right-click on it and select "Properties" to see what its size in pixels is and what file format it is. If it's a GIF and 64X64 pixels or less, you can just upload it to the DBB.
Well, you can take a screenshot of your icon in AIM by hitting ALT Printscreen and then pasting into any image editor. If you don't want to fool with cropping your icon out, just e-mail me a screenshot of that window and I'll do it for you. (click the envelope icon in my profile)