I was also reading up on this before we started ttc. I niaively thought that as I conceived my daughter whilst on the pill and using condoms, that it would be simple once we started trying. So, as I have a 12 year old daughter already, I started reading up on how to conceive a boy this time around.
Melanie is dead right about the boy and girls sperm, not an old wives tale at all. Believe it or not, it also helps with the position you BD in as well.

Have a look at this:
Frequency and Timing of Intercourse:
Shettles says in order to increase the chances of having a boy, you should have sex now earlier than 24 hours before ovulation to 12 hours after ovulation.
Intercourse closer to ovulation the faster but less robust Y (boy) sperm. The cervical mucus present at ovulation is less acidic and "slippery" enough to help the Y (boy) sperm reach the egg more quickly.
Sexual Position:
Shettles suggests that if you are trying to conceive a boy, deep penetration from your partner, preferably with the "doggy style" position, will deposit the sperm closer to the cervix giving the more aggressive and quicker moving "boy" sperm a head start to fertilizating the egg first.
Sex and Orgasms:
When trying to conceive a boy, Shettles suggests that orgasms during sex are a good thing as the body produces substances after orgasm that makes the vaginal environment more alkaline, which favors the "boy" sperm.
The contractions which accompany an orgasm help move the sperm up and into the cervix, giving the "boy" sperm an extra chance at being available when your egg is available for fertilization.
Considerations for the Men:
Have your partner wear boxers. Wearing tight fitting underwear increases the heat levels around the testes and can, in turn, lower the sperm count. Wearing loose fitting underwear helps keep the testes cooler.
Have your partner drink a caffeinated beverage right before sex. This makes the Y-Sperm more active.
Hmm, there's more to this ttc than first meets the eye!!!!