what can it do? I guess more than you'll need. PHP, in combination with *sql, gives possibility to build a portal of any size and at the same time isn't difficult to learn. PHP's main page shows the growth of php language in the net:
http://www.php.net/usage.php
and numbers are quite impressive.
Advantages:
among the obvious ones, is that
its easy easy to learn
code is clear for understanding and maintaining
its been said that php is faster than major league languages
with this new feature, GTK-PHP, it might be coming to the offline life soon
php is compatable with most db's
generating graphics on-the-fly is also a pretty good feature
as I say, these are some obvious reasons why to choose php over other languages, but the best is to know several and being able to learn a new language in the matter of days by applaying you previous knowleges.
cheers,
AlCapone