I think that ehow article is a bit over the top. Ammonium phosphate is no more toxic than common table salt...both have an 'LD50' (lethal dose for 50% of the population) of about 3000mg/kg body weight, meaning a 175 pound man would need to ingest about 9 ounces of the stuff to see possible toxic effects. Ammonium phosphate is also used as a 'yeast nutrient'
http://www.sciencelab.com/msds.php?msdsId=9927593 (msds table salt)
http://www.sciencelab.com/msds.php?msdsId=9927337 (msds ammonium phosphate)
For purposes of clean-up, I would treat both chemicals the same as table salt as well. Both the bicarbonate and phosphate chemicals are water soluble, so I'd probably pop the glass out, and give it a good cleaning and rinse in the sink. If the stuff is really caked on, you might need to let it set and/or use a stream of warm water to help the dissolving process.
The ehow article warns against water because they are discussing more of a room setting...if you spilled table salt on the floor or carpet, you obviously wouldn't throw water on it to get it up. Though if you spilled it on a dinner plate or a cooking tray, you could easily rinse it off...same with your glass.
Good luck!