mining and leatherworking dont really go well together, either go mining/engineering, mining/skinning, skinning/leatherworking
the second would bring in quite a bit of money at higher levels, but you wouldn't have a crafting profession, so you wouldn't really have any "burst income"
If you like to make things, then go skinning/leatheworking, if you could care less about making stormshroud armor at level 60 go mining/skinning
edit- and as for your first question, it is possible to change the account email address, but not the account name, just go to the warcraft home page and click on account management (should be near the to on the left menu bar if I remember correctly)
[Edited by insomniac, 12/20/2006 6:58:39 AM]
I'll probably have miinning/skinning cause i wanna make CA$H
hehe