|does that mean only ddr2 800 works and not ddr2 1000 or does it just mean that thats the only kind of 800 that works but others work as well?|
No. What it means is that it support or will read up to DDR2 800 but you can safely use DDR2 1000 modules, except! the modules will never be red at 1000mhz but 800mhz and yes, they would give you plenty of headroom for overclocking.
I used to have DDR2 1000 in my P5WD2-Premium and I was able to OC my ram pass 1000mhz.
So, you can sure use 1000mhz modules in the P5B Deluxe. But depends which modules you'll be looking at because usually, it's less expensive to buy DDR2 800 and OC it to DDR2 1000 speeds or even pass those speeds.
For example, the G.Skill I have cost $300 whereas the G.Skill 1000 modules cost $450, yet my $300 G.Skill kit can do the same as the $450 G.Skill kit, so it wasn't a good deal for me.
Which 1000 modules are you considering or it was just a question?