I was searching for this for awhile myself, and after finding a dozen or so links to dead websites, finally found a working one that took me to the kind of tool I was looking for. Figured Id share.
You put entire charsets that would have been compatible in RPG Maker 2003 into a folder and this program cuts out each individual character from the charset and sizes it correctly for Eclipse. It seems to even get rid of the background, which was a nice surprise. Does chipsets too.