What type of weed killer to ask?

I would like to know, is there a type of weed killer that I can use that will prevent the growth of weeds for the next few months up to next spring 2010, when I plan to put in sod. Right now all I have is nothing but dirt in my back yard. I removed all the weeds that were there. Something that can also tolerate rain and maybe kill ants and bugs as well. Something that when spring comes around it will be safe to put in sod. Any advice will be greatly appreciated.