How can I find/add the "Rx" symbol?

To save space with new events typing, I'd like to insert the prescription symbol (Rx) for my doctor appointments and trips to the pharmacy to pick up medications. I opened the Character Pallette but my search through the sysmbols section found no such symbol. Does anyone know where I can find a royalty-free image of that sysmbol. I'd like to use it in several other applications besides iCal.

Many thanks.