No. Not only must you have the card, but an OS that supports this feature. For instance, USB 2.0 support is non in Windows XP, but arrived in Windows XP SP1.
Be sure to note that item.
newegg.com and compgeeks.com have such cards for under 20 bucks.
I have a Dell Dimension 4300s that currently does not have USB 2.0. Am I correct in understanding that I can simply buy a Firewire or USB 2.0 card and slap it in the machine and it will work? I bought an iPod and need to resolve the connectivity issue here.