If you've never spoken at a conference before and you're not quite sure what to expect, you might check out this new post from Matthew Turland about how it all works and some of the common issues you might come across.
I can't make any claim to the title of veteran conference speaker. Not yet, at least. However, I have done it once before at ZendCon in 2008 and I'll be doing it again at php|tek this year. I thought I'd take a blog post to give out a few tips to any prospective first-time speakers based on my first speaking experience.
He gives a few recommendations like being ready to give your presentation before you even get on your plane (including practicing out loud), take some cues from those members of the PHP community that are the veteran speakers, don't depend on your (or the conference's) technology to come through and, most importantly, don't let critical feedback deter you from submitting and speaking again.