"I've tried to speak but my talks never get accepted"

My advice: go and speak at a BarCamp, or another Unconference. Everyone gets to speak, and it's a great place to start building experience as a speaker. Post your slides afterwards (and write the talk up on your blog) and you'll have something to point event organisers to. As you build a reputation as a speaker you'll find it much easier to get gigs at larger events.

Here's our list of barcamps http://lanyrd.com/topics/barcamp/ and unconferences http://lanyrd.com/topics/unconference/