where can i hook this

[khan3332]

i need to have

a plugin where everytime a user visits the forum

and if his username is a preg match of an email format

then it goes to another page i made

any idea where i can put this plugin?

i need something simliar to like the password expire thing

except its a place to change the username

[Xenon]

global_start would be the best position i'd say