You can use any bench stone to perform this task, however, if you're not that experienced with benchstones then the easiest route would be the Sharpmaker. It really does work great for many sharpening tasks and I would definately include scissor sharpening as one of those tasks.
Also, if the scissor blades are not knicked but just dull then you can use a sharpening steel (butcher's steel) instead of a hone. I prefer a glass smooth steel but you good probably use a lightly grooved steel as this may be a good in between choice rather than re-aligning the edge (using a smooth steel) and sharpening (using a stone). Plus, you more than likely already have a grooved steel in your kitchen right now. You might as well go ahead and try this before committing any hard earned cash on one of these other choices.
Either way, remember that you should only sharpen the chisel side of the blade (not the flat side). As mentioned by Don Luis, the majic marker trick is always a good tool to use when sharpening. It helps teaches proper angle alignment when sharpening.
As for the burr that's left after sharpening? You can either run the flat side of the blade (using a single pass or as few as needed) on a leather hone or just do as most people do and open and close the scissors a couple of times. Yup, that works quite well indeed.
--The Raptor--