My HP Pavilon N5412 as two PCMIA Slots. Situated one below the other.
My problem is that I have two PCMCIA Cards. One a wireless card and
the second a 4 slot usb 2.0 hub. But I am unable to use them at the
same because once one is inserted its physical size. Prevents the
second card being inserted. Does anybody know a way round this
problem. Is there any adapter available that can be inserted into one
slot to bring it outside of the laptop. i.e. some kind of extension
lead.

I'm not sure if any of these actually have the geometry to do what you
want, but they sound like the kind of device you're describing:
http://www.twinind.com/catalog.php?id=5#sc12

Found by doing a Froogle search for "PCMCIA extender".

kime1r-ga thanks for your comment I have also come across the
extenders. But they only seem available in the USA.I reside in the UK.
But it is an avenue that I may have to go down.

Have you a USB port ?

If so you could get a USB -> PCMCIA adaptor