I've heard different philosophies when it comes to writing inspiration. Some writers write only when they are "inspired". Others find it more productive to write & write & write until inspiration hits. I've tried both.
For me, I find that I need to do something every day-even if I don't feel like it. Otherwise days turn into weeks, and weeks into months, and before you know it I haven't written in such a long time that I need to requaint myself with the story and the characters that I've developed. I love writing, but believe me when I say that there are certainly days when I find a million things to do before I commit to sitting down and putting some words on paper (or computer).
So I do a number of things to get myself inspired. Sometimes, I will just force myself to sit at the computer and write, anything, write & rewrite the same sentence 20 times if I must, but write until I get through that hump that is blocking me from moving on in the story. This usually works well when I know I have a good block of time, usually a couple hours, to work through it until I'm at a point where the words are flowing again.
Another tool of inspiration is reading quick stories, articles, blogs, or website snippits from my writing idols. I keep these saved under my "favorites" for easy viewing. Having the connection with other writers, even if I don't know them, helps me feel part of the community, and reignites my excitement...specially if I read their stories of struggle and ultimate success. Here are some links to my favorite authors:
Stephen King: http://www.stephenking.com/index.html
Stephenie Myer: http://www.stepheniemeyer.com
Christopher Paolini: http://www.alagaesia.com/index.php
J.K. Rowling: http://www.jkrowling.com/accessible/en
John Flanagan: http://www.rangersapprentice.com/
Terry Goodkind: http://www.terrygoodkind.com/
John Grisham: http://www.jgrisham.com/
David Baldacci: http://www.davidbaldacci.com/web/
I also keep earmarked passages from my favorite books handy. By reading a few paragraphs I get excited about the story again, about that author's style, and ultimately about my own writing.This has served me on quite a few occasions.
And finally, I find inspiration by going to bookstores. I love the feeling of knowing that every book on the shelves has its own story, unique characters, and perspective. All of those authors found a way to get their stories finished-they found the inspiration they needed to make their stories come to life. It gives me the hope & inspiration I need to finish my current project, so I too can add my contribution to that selection.