This is going to end up being more of a Quotes page than an Advice page. For specific advice on writing I would suggest reading the How to Write and What to Write sections. In addition, you would also benefit from checking out Writing.org.

I continually refer to J. K. Rowling here, but I feel that is with good reason. She is arguably the most successful author of all time, and seeing how you and I are aiming to become published authors ourselves, it would be in our best interest to listen to such a successful role model. That being said, this is the one quote from J. K. Rowling that I consider to be of most relevance and importance for aspiring authors. When presented with the question, "What advice would you give to [young] writers today?, her response was this:

"I doubt a writer who has got what it takes will need me to tell them this, but --- persevere!" - J. K. Rowling

More quotes on the way!
Last updated September 26, 2007

All work and no play makes even the most devout of writers a little insane. Thus, Grey Pinky has introduced the Pinky Gallery, where all writers can proudly stand up and display their.... Gotcha wondering, haven't I? Feel free to check it out for yourself.

Links

Writersservice.com - This is a huge site with a tremendous amount of information. The link provided here is to the literary agents' page which has some good general information for aspiring authors looking for an agent.
Writing.org - Another great site with info for authors trying to get published. There are a number of articles, everything from how to write to how to best approach an agent and much more.