To nate, who advises that there is no reason to use an unsigned version of the IP in a MySQL DB:
I think it would depend on your application, but personally, I find it useful to store IP's as unsigneds since MySQL has 2 native functions, INET_ATON() and INET_NTOA(), which work the same as ip2long()/long2ip() _except_ that they generate the unsigned counterpart. So if you want, you could do:
-- IANA Class-B reserved/private
SELECT * FROM `servers`
WHERE `ip` >= INET_ATON('192.168.0.0')
AND `ip` <= INET_ATON('192.168.255.255');
In my current application, I find it easier to use the MySQL built-ins than the PHP counter-parts.
In case you're curious as to the names ATON and NTOA:
ATON = address to number aka. ip2long
NTOA = number to address aka. long2ip