The first thing to get when making rainbow text is that every thing you see on a website is a graphic.

the background is a graphic, images are graphics, the letters are made with files of graphics.
these files are called Fonts. there are literally hundreds if not thousands of fonts out on the web. the one webtv uses most is arial.

here is our assistant Marcellus, Oh,Marcellus,where are you?

There you are! he was asleep under the desk {o.g.p. is off on an exchange assistant program, marcellus here is graciously taking his place for this lesson} Jet lag, Marcellus? anyway, Oh, yes... however we have the option of using IM(imagemagick) to make letters in different fonts.
let's look at the word Rainbows in several different fonts, shall we?

Pretty boring,but it is what we webbies see regularly. that's right, it is... ARIAL
marcellus thinks She should go back under the sea.

let's try a gothic font

different but not exactly what I think of when i think of Rainbows.

this one sounds interesting.

still not it,

we'll try this one,

That's more like it.

by the way the fonts used were fletcher gothic,black chancery, and one I have in my files http://spirtbones.org/byeyou/yes.ttf the first are in IM when you go below the annotate button in a jumpbox type thing. they are all usable to annotate things there. another way to find fonts is to go to
captainraider's
font repository or
phillips fonts at onnet-z.com

Once you have your lettering we can start to make some rainbow text...