Transfer of Wordpress.com domain to personal domain for adding adsense,paid posts,JV

[amIT]

hey I have one wp domain.. i.e xxx.wordpress.com
it has pr 4 and really want to put some adsense into it...i have some personals domains too.http://www.v7n.com/forums/images/smilies/lol.gif

My question
1.) what will happen to my pr If i map my wp domain to a newly bought domain

2.)is adsense and paid posting allowed on wp domain even after it is mapped to other domains??

3.) after hosting on new domain which url will be redirected
( i mean will xxx.wordpress.com domain be directed to my new domain or my domain directed to xxx.wordpress.com domain)


4.) The hosting account needed to transfer the DNS ..does it have to be