I noticed that using iStumbler (OS X) my network's MAC address is obtainable on my router's front end. Is it possible to get an IP address from the MAC address?

I'm not sure what you're asking here. Are you asking how to get the IP address reported to you by your router, like the MAC address is being reported? Or, are you asking if you can tell what your IP address is from reading your MAC address? Or...have I missed the point completely?

If you are wondering if you can tell the IP address from the MAC address, the answer is no, you cannot. If you want your router to give you the IP address, it can, IF the router is your DHCP server. Your DHCP page should have the leases it is giving out, listed.

I'm worried about being able to obtain my IP from my MAC address since the MAC address is easily visible... I heard that Warp/OS had a program that could do that.

Basically I worried about the security of my wireless network... plus i would like a way to spoof my MAC address... anybody know how?

arp -a

or

arping

I'm talking about an actual router... think lowend... airport router... will that still work? And how?