So I'm scared off by facing the Sicilian as White; I play d4 exclusively.

I'm hoping to play in a few OTB tournaments in the upcoming months before I head out to boot camp, so I'd like to bone up just a little bit on my opening knowledge since I think USCF frowns on Opening Explorer use.

I also tend to play the Catalan against 3...e6 because the Nimzo-Indian is a bit sharp for me, and I have a bit of understanding about such a position.

Nigel Davies (who is a great author) is coming out with new Catalan book. It's called "Play the Catalan" and it's going to be release in May 2009. Here is a link to Amazon.

http://www.amazon.com/Play-Catalan-Starting-Nigel-Davies/dp/1857445910/ref=wl_it_dp?ie=UTF8&coliid=I1MNWS39CP4KY5&colid=2906279JYBBNY

Also, check out "Starting Out: 1d4 : A Reliable Repertoire for the Improving Player" by John Cox. It's not really deep but has great overview of various d4 options

http://www.amazon.com/Starting-Out-Reliable-Repertoire-Improving/dp/1857444175/ref=sr_1_1?ie=UTF8&s=books&qid=1236200112&sr=1-1