Copy wordpress

I am wordpress user .

I had been using wordpress on some .co.cc domain . Now I want to move on .com . But due to extra promotion i had always used bit.ly url . If i removed the old wordpress and make new all links will be breaked .
SO i want that all links should also work and new also

In simple words , is there any plugin so that when i post a new topic in my 1st blog that it is automattically post on 2nd blog ??

Thanks !