What does 'Hie' mean on your planet?  Please refrain
from using local slang when posting, as it makes you
appear foolish.

Possible yes.  Practical, no.  Applets embedded in web
pages have a great number of problems.  A JMF based
applet in a web page adds to those problems, and a
'full-trust' JMF based applet just *multiplies* the woes.

To work, it would need the client (end-user) to not only
separately install JMF, but also to think to select 'allow
sound capture in applets' when installing - by default it
is 'false'.

(And that still leaves you to deal with all the problems
that might crop up from using plain old applets in web
pages.)

Note that JMF is a (popular but) abandoned API.  Sun is
looking to introduce the Java Media Components Framework
in Java 7, which will leverage the power of the system's
default player.

Is going to Java 7 a possibility?

Few people are.*

Ultimately, I cannot understand why anybody would
want a browser window wrapped around a media
player (or video conferencing tool).

Fortunately, there is a far better alternative.

Java web start (JWS) allows you to launch an application
or applet from a link on a web page.  This results in a free
floating app., here is an example.
<http://www.physci.org/jws/#jtest>

If you are looking to use web start, it is probably best to
avoid the applet altogether and go directly to an application,
as JWS launched applets are not resizable (without a bit
of hacking).

JWS can supply all the jar's and DLLs required to make
the app. work correctly, and is not subject to the same
restraints as imposed by the installer.

I had an example of using JWS to launch JMF, but
unfortunately it is off-line for the time being.

* And as an aside, I noticed your 'me too' style
addition to the "Video Conference over INTERNET
code!" thread on the Sun JMF forum.  If the original
poster was anything less than a complete pillock,
they'd have refrained from making that post altogether,
it is an utter waste of time and bandwidth.  I note
that one single (sensible) poster to that thread either
alluded to that, or stated it.  Please take the hint.

Since you were asked to use PHP, I would think you should be looking
for video conferencing packages that are designed to interface to PHP.

Only after you exhausted that would you be looking for a Java-too
solution.