I issued 6 postdated checks for the rent, payable on the 1st of every month, from July to December 2009, say for example, each check is for $ 2,000.00 Please tell me what is the best way of journalizing this?

Please tell me you didn't really do this... I really hope this is just a homework question because it does not matter what date you put on a check it can be cashed on demand regardless of the date on the top.

Also this doesn't seem like an actual pre-payment as you are assuming that the checks in question will not be deposited until the date on top. Therefore where is the payment? It hasn't been made yet so its not pre-paid.