Still if you want P8ntballer infamy, DMA will be the place to be. Baller X got a standing ovation from what, like everybody at the event when leaving the "special room".
Have a look here http://www.bastionhotel.nl
They got hotels all over the country, including a number of them in Amsterdam. They are not bad at all, and not too expensive.
Just hit the little Union Jack on their site if you can't read Dutch...
Looks like it'll be in the same place as last year. I'll look which hotel of that chain is closest by.
In the meantime, www.dma2005.com has a hotel link up.
You'd still need transportation though. There aren't really any hotels within walking distance of the site. But for the more hardcore amongst you, there is a campingsite across the road from the site.