R – dectect sifr is active on page

I think it's a con to using Flash to render text. Have you considered using a server side language to generate text or typeface.js ?

Or better still, can you use a web safe font, or is the client the type that won't budge?

Edit

You may be talking about FOUC ... Flash of unstyled content. This generally is an IE issue with stylesheet placement, but I've seen in it Safari before too. There are generally workarounds for this.

I would recommend you look at cufon (google it) if you want cross-browser based font replacement that doesn't require users to have flash