Just got the book that was suggested by Wonderwench above called "Baby Girl or Baby Boy: Determining the Sex of Your Child Explained in Plain and Simple Language". Basically, it gives the same technique that Boo gave above. It also suggests that for making a girl that the man should reduce his sperm count. This means lots of sex just before trying for conception. I think I really like this book
. I'll let everyone know how things work out (probably in about a year or so).