Also a six part mini-series that tells the beginnings of Marvel Comic's Wolverine.
Despite some fan protests, Marvel decided now was the time to finally reveal Wolverine's past, after 27 years. One of their key motivations was the fact that they wanted to tell the tale of Wolverine's history before Hollywood did it for them.
As fans know, the X-men movie ended with the Wolverine character going off to find out about his past, and with a sequel coming out in the following years, Marvel decided it would be best to tell it now before some script writer makes it up for them.
Oh yes, and I'm sure the fact that it's going to be a collector's item, and sell extremely well had nothing to do with their motivation. :)