The English could use some tidying up. Lines like this won't help you:
I pride myself in my commendable expertise in creating ... cross-browser compatibility issues.
:eek: That actually means that you cause problems.
Here's a possible alternative:
I am a skilled web designer, with expertise in front and backend development (HTML, CSS, PHP, MySQL). I also specialise in a range of content management systems—including WordPress, Magento, Adobe Business Catalyst and Weebly—and can assist with the building, debugging and project management of both new and existing sites. My work includes a dual focus on web standards and opportunities for maximum return on investment for websites and web apps. I am friendly, flexible and proactive, and look forward to working with you on your next project.
This is just something I quickly knocked up and can probably be improved greatly. Perhaps others will help refine it.
I do wonder, though, if this is the right focus for something like oDesk. What kinds of jobs are typically posted there? If they tend to be small items like a bit of debugging here or a tiny bit of coding here, it might be better to focus on how well you do that sort of thing. I don't know, as I'm unfamiliar with the site. Just a suggestion / question.