[Logician]

yes it's possible with bbcode and iframe.

Create a new bbcode in your Admin CP, here is the details:
vB Code tag : window

vB Code replacement:
<div align=center><iframe name="cwindow" style="border:0" width=500 height={option} src="{param}"></iframe>

vB Code example
[window=300]http://www.altavista.com[/window]

vB Code explanation: IFRAMEs URL

Use {option} ? YES

afterwards you can use it in your posts like this:
[window=300]http://swishzone.net/SZO2003/includes/tom.php[/window]

And it will be converted something like this: