Here is how I labelled my buttons.
This would only apply to lighted buttons with the removable domes.
Step 1: Go to Staples and buy a pack of 3/4 clear round labels. (I'll post a UPC later)
Step 2: Download some off the wall, awesome, theme-fitting font from 1001freefonts.com or some other font website.
Step 3: Go to the avery website and download the MS Word template for the above labels.
Step 4: Use you awesome creativity-ism to make and print the labels.
Step 5: Disassemble the button and apply the label to the little diffuser disc inside the button.
Step 6: Trim off the excess label using a pair of sharp scissors and an x-acto knife. It doesn't have to be pretty because the cap will hide any ragged edges.
Step 7: Reassemble the button.
Step 8: Enjoy.
I'll post some pics and a UPC number for the labels ASAP.