There are a ton of websites out there about Valkyries, Macross and Macross model kits. Here's a few I frequent:
http://www.macrossworld.com/
http://www.starshipmodeler.com (look under Mecha and then click on Macross)
http://www.steelfalcon.com/macrossmecha.html
http://macross.anime.net/
http://nanashi.macrossmecha.info/
Robotech was the "americanized" version of Macross and was composed of 3 different Macross sagas, cut & pasted together, edited and somewhat censored for the U.S. TV viewers.
Regarding Macross-related model kits, Hasegawa has released quite a few of them the past couple of years. Revellogram (Revell at the time) repackaged some of the Bandai kits of the time and resold them in the U.S. as "Robotech Defenders", and you can still get the Bandai kits today (although retooled and a tad improved).
The Bandai Valkyrie kits are usually transformable between battroid, gerwalk and fighter plane. The Hasegawa kits are not transformable (you have to buy the fighter and the battroid separately) but they do have the Hasegawa quality and attention to detail. Excellent kits IMHO.
Best places to buy Macross model kits:
http://www.hlj.com
http://www.gundamstoreandmore.com
http://www.rainbowten.co.jp/english/
http://www.valkyrie-exchange.com/
http://www.ebay.com
http://www.hobbyfan.com/
Hope this helps. Enjoy!
-- Like, whatever and junk.