You can also use "&GreekLetter;" Put the first letter of the greek letter in capitols to get a capitol, in lowercase to get a lowercase letter.

example:

& Alpha ; (no spaces, semicolon important!) = Α

& alpha ; (no spaces, semicolon important!) = α

It doesn't always look quite as nice (I think), but it does mean that your greek letters show up even when someone doesn't have the symbol font on thier computer.