yeah... very safe to order online. sometimes even cheaper. the only downfall is that stores usually wont mount them for free unless you buy them there... check into it. a lot of tire stores will order any tire you want... in which case they usually mount them for free.
Discount/American Tire does this i know.
if you do order online... try these sites:
www.tirerack.com
www.discounttire.com
good luck!