Dispella is a small and simple addon which shows up to four of your dispels (including Spell Steal) in a moveable frame.
The frame can be moved by typing "/dispella" and then simply dragging the addon to the desired location on the screen. Type "/dispella" again to hide the anchor.
This was a small addon which I used to get myself started in creating addons so it's very basic, although that's probably perfect for this.
I'll work on adding a few basic options once I've familiarised myself with saving settings.