Hi to all the newbies!
marshmallow the reason they say to allow yourself a "natural" period is so that it is easier to work out when you conceived. Of course with scans these days it can all get worked out at a later date, so it's up to you if you want to get cracking or not 
I don't want to be the boring "harbinger of doom" around here, but I will say to all the newbies, please don't put too much pressure on yourselves to conceive right away. A perfectly healthy couple with no fertility issues will usually conceive within 6 months to 1 year, but you have to bare in mind that it can often take longer. I know what it feels like to put pressure on yourself to get pregnant right away, after all we have it drummed into us that any unprotected sex = pregnancy, but please do take the time to be kind to yourselves.
I read something in one of my many conception books that refers to the "missing 3 months" of pregnancy. This is the three months you should take before you conceive to get yourself healthy, give up any naughty habits and generally prepare your body for pregnancy. It is definitely worth baring in mind.
Also, don't forget to start taking your folio acid NOW - they recommend you take it as soon as you think about ttc.
Just call me Headmistress Cave 