How do I know if a DVD blank is dual layer?

I just bought a dual layer all format DVD burner. How do I know if a DVD blank has dual layers? What should the DVD blanks say to indicate they are dual layered? Are there any dual layer brands better than others? How much should dual layer blank cost?. I use NERO. How do I tell NERO to burn to a dual layer blank?
I want to burn to a dual layer DVD blank so that I dont have to compress the Video file.
Thanks!

The disk or packaging will have either DVD+R DL or DVD-R DL designating it as dual layer. If your version of Nero is fairly recent, (I use version 6) If you create a DVD image, that bar along the bottom will show 8.5 GB as the max capasity. If you try to burn 8.5 GB to a single layer disk, Nero will alert you before it tries to burn. pricing as I have seen it is around $2 per disk when sold on spindles. Shop around and you may find better. I have never used DL disks so I can't reccommend a brand.

Verbatim is the best brand for DL's I think. I've so far burned 9 DL's without any issues from them. I've heard bad things about the Memorex's, but thats hearsay.

True, they're rated at 2.4x, so a full DL takes about 40ish minutes to do. If you have a faster DL burner, the verbatims should be able to be pushed a little bit to go a little faster.

DL produces the full DVD quality movie, just like you buy in the store. Typically all movie DVDs in the stores are DL. If you want a movie-quality DVD, it only fits 1hr on a DVD-/+R. Of course you can always play with the bitrates to get it to nicely fit on a DVD-/+R or a DL.