well, considering that you cannot use php in your own profile, i don't think this will work. let me clarify my problem:
assume my screen name is "coolguy." in AIM, there are many ways to format this, so let's see 2 examples:
case 1: %n="coolguy"
case 2: %n="cool guy"
(%n being AIM's built-in function of reading someone's screen name)
<a href="yourwebsite.com/profile.php?sn=%n&a=b">Profile</a>
in this case, an external browser (like IE) will open it, and both cases works.
<a href="yourwebsite.com/profile.php?sn=%n&a=b" target="_self">Profile</a>
however, in this case, the internal browser (AIM) opens it. the first case works, but because there is a space in case 2, that does not work.
somehow, websites that are dedicated in doing this (subprofile, IMchaos, etc) have found a way around this, even for case 2...