"Pulsating" effect...what's the proper method?

I have frame "frame". I want it to fade from alpha "1" to alpha "0", then back to alpha "1" and repeat until I say otherwise to make a "pulsing" effect.

I tried doing this in a manner like so, and...well...yeah, infinite loops are bad.

while myvariable = 1 do
    alpha = frame:GetAlpha()
    if alpha = 1 then
        UIFrameFadeOut(frame, 1, 1, 0)
    elseif alpha = 0 then
        UIFrameFadeIn(frame, 1, 0, 1)

Hello, Mr. Client Crash.