Centering in XHTML

[Trip]

Ran into a bit of an issue and hopefully someone could shed a little light on the subject. I am working on a new site, I have the Welcome Header mod by Ted S installed. I didn't want the search spiders indexing the guest welcome message, so I created an image and using DW created a XHTML "traditional" code to display the message without it being indexed. Problem is my theme is fluid and I would prefer this "image" being centered so its still visually appealing. According to most/all of the research I've done the "center" tag is deprecated. I through it in there for now, but does anybody know a way around this or have an opinion on a direction I should take??