They sell them
here. It also gives a little back to ENworld (just bought some more dice from here a few days ago and the service is great). I have also purchased from
www.roleplayer.com in the past. They have prices that are a little better but it takes much longer to get your items (10-14 days vs. 3-5 @ base shipping).
I own the purple & orange sets and have seen the clear, green, red and blue @ my comic shop. They are all pretty cool. They look kinda girly at first because they seem to have some sparkles in them but upon closer inspection this is not entirely true. The effect is that of a constellation seen through a high powered telescope or (as the name suggests) an aurora borealis viewed in a place with low light polution.
I purchased the orange set because I have a thing for orange dice (don't ask). I picked up the purple set because I needed something purple and they looked cool. You can't go wrong with the blue set or the red. The green looked good, but I have seen cooler looking green dice like
these &
these. The clear aren't bad either but I would go with a set of
frosted dice (better price, simply cooler looking) before I bought the clear Borealis set.
Hope that helps. Happy rolling.
And yes, I have too many dice.