Find a series of likely publications that you think your work would be appropriate for and make direct contact with them. Include a link to some examples of your very best work. Apply to various photography magazines for their "featured" sections (most mags feature photographer's work each month) as well.
Keep trying to make contacts, make sure you get to a variety of exciting locations and keep promoting yourself.
Putting photos on the internet doesn't mean the work will come to you, you need to get out there pushing yourself and getting in people's faces and really do the leg work. It will be tough going and the whole process might take 5 or 6 years before you start getting a decent hold.
Avoid mentioning you're happy to work for free. A lot of magazines / publications will pay their photographers as a matter of course and working for free just undermines and de-values those out there doing it for a living (you hope to be one of these one day I would imagine so keep that in mind).
I offer images free of charge to good causes and non profit organisations and I say as much on my website. If the photo is required for a commercial venture, they will be making money from it - it is a business, they wouldn't expect their printers to produce copies of their magazine for free would they?