If your expected date of delivery is 24th May, 2010, then your approximate date of conception can be 31st August, 2009. This approximate date of conception because exact date of conception can not be figured out because ovulation can occur at mid of the cycle, early or late. Egg after ovulation can live for 12-24 hours. Sperms can live alive for 3-5 days in female body after ejaculation. So, when you ovulated and conceived is assumed by considering normal conditions that you have 28 days cycle and ovulated at mid of the cycle.
You conceived some were at the end of august
Congrats! I was asking the same question because I'm also due on may 24th, 2010. :)