When my boys were babies there was almost nothing for boys and I thought that I wouldn't be able to make things for my guys, until I realized that there's little difference between baby girl clothes and baby boy clothes other than the color of fabrics and the addition of lace. The basic shapes and pattern pieces used to make clothes for babies is the same for girls and boys, all you need to do is choose "boy colors" and fabrics and leave of the lace trims, ruffles and cute bunny appliques. For boy themed appliques you can trace pictures from coloring books, that's what i did. Or not bother as appliques are needlessly time-consuming and let's face it, baby doesn't care about trucks on his sleeper.
Simplicity has a wide range of baby patterns: http://www.simplicity.com/c-156-babies.a... For example this simplicity pattern: http://www.simplicity.com/p-4478-babies-... if you ignore the dress, the romper and the onsies are suitable for either boys or girls. Again, with this set:http://www.simplicity.com/p-1815-babies-... forget the dress, eliminate the ruffles and use twill fabrics in blues, browns and greys and you have some nice boy's creeper/rompers in short and long pant versions.
Kwik Sew has an even better array of baby patterns: http://www.kwiksew.com/catalog/cat_thumbs.cfm?End=25&Start=1&Cat=Children&Level=Babies&QL=Babies that are easily adapted for boys and several that are designed for boys specifically Kwik-Sew also has a fabulous "Sewing for Baby" pattern book that's filled with easy to make patterns for clothes suitable for either boys or girls. The patterns and instructions are all included in one book and you can make lots of nice pants, tops, rompers etc: http://www.kwiksew.com/catalog/Book_Baby.cfm?Cat=Book_Baby
If you want some free patterns for the web there are many to choose from. Some free patterns are worth exactly what you pay for them, while others are better. Free patterns usually are for blankets, booties and other easy projects but there are some clothing patterns. Here's some places with lists of patterns:
That should get you started!
With two showers coming up, do NOT buy anything until you get through those showers--EVERYONE will give you clothes and diapers. It's amazing.
Also--you'll probably not need a huge selection of clothes RIGHT now. We shopped around at discount stores like Burlington Coat Factory and Gordman's, but also ask around if anyone has had a son and would mind sharing a few clothes.
But like a I said--don't go ga ga over the clothes just yet and remember that sometimes you'll be using the clothes just a few times before he outgrows them.
Plus buying now causes some problems in that it's still hot, and while it won't get TOO cold in California, the clothes will change slightly for winter.