HTTP POST Firewall Work around? - PayPal IPN

Hey,

I'm trying to set-up a PayPal Instant Payment Notification backend to a
site. The problem is that I cannot post back to PayPal using
"fsockopen()" since my service provider (1and1.co.uk) blocks outgoing
HTTP connections because this "binds a port".

Does anyone know any workaround at all?
Have other people using IPN just used fsockopen?
is cURL an option? (I assume not but I have no experience whatsoever
with it).
Someone else mentioned IFRAMES once??

Thanks in advance...

(Slightly doomed...) Adam