So you're a workaholic, eh? Nothing to be ashamed or afraid about there. It's basically the same as many other addictions, though somewhat more sanctioned by society than others.
This book  suggests that it's basically the same as being addicted to adrenaline. And an addiction it is.
A few thoughts in passing for addicted workaholics.
Typically there is some underlying cause, or reason, why you have grown to love work so much. Does it give you a sense of worth? A sense of control? One way to help is, when you feel the urge to go and work, write yourself what "Men are from Mars, Women are from Venus" calls a love letter (explanatory letter). This can be great to help you understand yourself and what the emotions is coming from.
Once you know the "real" root cause you have some more information. You can try to fight that (the real root cause), or to just control the symptoms (the work-aholicness). The book "chained to the desk" kind of does the latter, suggesting some treatments to kind of combat your specific "type" of work-aholicness. Which is useful. It's kind of like treating alcoholism--you may find benefits from treating just the alcoholism, as well as treating the underlying problem (ex: somebody that doesn't feel love at home, so they go out to drink at night--they may benefit from both feeling more love at home, and overcoming alcoholism they have developed). Habits aren't developed overnight so expect something of a battle before you overcome this one.
Another good resource is "workaholics anonymous" which basically has some support groups scattered across the country, and also a workbook and a book that they publish with some good resources. Unfortunately you have to pay for the workbook/book, since I requested an online copy but they said they needed to keep charging in order to stay solvent.
If you find your work aholicness seems caused by an inner void, this book is quite good (basically treats with discovering why you feel that way, based on your parents typically, and how to fix it).
Another good book is "the anatomy of peace" (or its predecessor "bonds that make us free").
Anyway good luck on your journey, and you can do it. Feel free to add to this page as it is a wiki page.
 Chained to the Desk and no I don't get any kickbacks from amazon for listing it here :)