My suggestion:
CREATE TABLE `users` (
`id` tinyint( 4 ) DEFAULT '0' NOT NULL AUTO_INCREMENT ,
`username` VARCHAR( 25 ) NOT NULL ,
`password` VARCHAR( 25 ) NOT NULL ,
`ip1` VARCHAR( 15 ) NOT NULL ,
`ip2` VARCHAR( 15 ) NOT NULL ,
`ip3` VARCHAR( 15 ) NOT NULL ,
`user_url` VARCHAR( 25 ) ,
`user_email` VARCHAR( 25 ) ,
`user_sig` TEXT,
PRIMARY KEY ( id )
)
I don't know the lenghts of ip-fields were 25, but changed it to 15, because 4*3+3 is 15. You can't define maxinum lenght with TEXT field, which was the primary problem, thought.