if it doesnt help dont worry just post your sig here i will have a go for ya
if you want a transparant background on your image dont use shadows or outer glow efects on the areas that needs to be transparant eg parts sticking out of main image
NOTE: i use photoshop 7 .... i allway use GIF file type as well NOT PNG ... if you use a later version of photoshop iam sure there not that different
i work most of my images in photoshop image ready then transfare the image to photoshop to make the image transparant
these are just screen shots i made they might help !!!
use this button to tranfare your image to photoshop

use this setting to set the matte to NONE this is the transparant part make sure your on a GIF file type as well

click on save from here and just name it test or anything you can delete it later THIS MUST BE DONE
now go to your taskbar and click on photoshop image ready the changes you have made will be transfared over you can now click on File / Save Optimized As change the name of the file in some way
the following images where all saved as PNG file types they should of been GIF and the matte should of been on NONE again DONT use shadows and outerglow i did a little editing to try to keep the quailty of the images but some i cant

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[IMG]http://i96.photobucket.com/albums/l176/tyro_album/faerie-sig-smalleditbackground.gif[/IMG]

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[IMG]http://i96.photobucket.com/albums/l176/tyro_album/SupermanGTR05bfixed.gif[/IMG]

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[IMG]http://i96.photobucket.com/albums/l176/tyro_album/sphxdsrgts-background.gif[/IMG]

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[IMG]http://i96.photobucket.com/albums/l176/tyro_album/vampiresig1bcopy3.gif[/IMG]

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[IMG]http://i96.photobucket.com/albums/l176/tyro_album/Completed.gif[/IMG]