BeerBorg

This may be a stupid question BUT
Whats the difference between the two?

I believe the Bohemian is just grown elsewhere...it's a special order at my LHBS.
I'm sure you can find an analysis sheet online somewhere that might explain the differences but I doubt that they'd be major.

I think Bohemian pilsner is Czech grown.

American Pilsner to me seems to have a less deep flavor then the various European grown pilsners (all of them do taste a bit different side by side, some a bit sweeter/more grainy, some have a very slight underlying fruitiness, etc). BUT you would probably only notice it in a beer without much if any other kinds of malt. I can notice it if I make something like a Patersbier or Blonde that is nothing but pils. I like the results either way, and I'm happy to use MoreBeer Pils extract for those things too - but they are a bit better with real Belgian Pilsner. If I was seriously trying to win an award with a beer like that I'd mash the Belgian stuff. For lawnmower quaffing, not so much.

Also American Pilsner is more highly modified and converts quicker at low mash temperatures. If I mash Belgian Pilsner at really low temps in a single infusion mash, I can take 90 minutes to really be "done". Even at moderate temps, I go 75 minutes. My bet is it's the same with other Euro Pilsners too. Those things are ideally used in a multi-step infusion or decoction mash if you have the time/capability.

Bohemian, Czech (City of Pilsen) is the original pilsner. It is brewed with very soft water vs the harder water of Germany. Of course there are the different yeast strains used to. Pilsner malt is usually the lightest colored malt available. You can brew a perfectly acceptable Pilsner using two-row, it will be a shade or two darker.

@Brauskeeper, I believe he was asking about the actual malt vs. beer style.

Yes you can brew a pilsner with American 2-row. But it will not just be colored differently, but also taste slightly different. That doesn't mean bad. Nor does it mean wrong. But different. Especially in a lightly bittered, lightly hopped beer you can notice the difference between American Pils, German Pils, and Belgian Pils, as well as American 2-row and continental pale malts. One will be more "grainy" one will be a bit sweeter, one may even seem a bit fruity.

So it depends on if you care about different.