You got it a little confused. You use PHP directly in the plug-in and then place the HTML you want into a variable to be displayed in the template...

Here is a quick example of what a plugin would look like with your first if statement....

Then you would place a reference to $alnav into the template

Probably the easiest thing to do is to use output buffering.
E.g.
Use $somevar in your template

thanks for the help i'll give it a go

--------------- Added [DATE]1216814486[/DATE] at [TIME]1216814486[/TIME] ---------------

as a test i ran this:

nothing shows... and whenever i enable the plugin i get this error:

Fatal error: Call to a member function on a non-object in /home/forcer/public_html/forums/includes/functions_forumdisplay.php on line 182

thats with the hook global_start, when i use the hook global_setup_complete i get an error at the top of the page.

If you are using
then you need to put the \ before any 's in there
like

Besides what was said one post above me, that code their would go directly into a plug-in without the output buffering OP mentioned. If your using output buffering nothing will show up. Output buffering is for times when code executes and echos or prints data instead of storing it in a variable, it allows you to take what would be outputed directly to the browser and store it. Like your original post that has code, if you took out the variable and quotes, all the code you have in between would need output buffering.