scripting help needed for intresting mod

i have thought it would be good to be able to give users an option to have a webcam stream in there profile page, u can stream your cam with various software and would would use an embed code with http://123.123.123.123:8080 as an example i need help figuring how a can have a line of script to go on the profile page that would know what the user id is for page and then take the users current ip address like in the whos online page and add it into a url pehaps using bb code or summat for the replacement value? ie

http:// [insertt ip bb code] :8080

so whole process would be
1 profile page to find username on that page
2 do a lookup like whos online for latest ip
3 insert into a string ie url

is there something like $member_ip or sumething that could be used? how does whos online script find it?

this would be a great mod if we can find a way
all help appreciated