Hi,
Port 5190 can be moved within iChat.
Go to the iChat menu > Preferences > Accounts
Click once on the Account is question.
Click on the Server settings tab on the right.
Change the port from 5190 to 443
This will let you Text chat at least. Some people find they can then Video as well.
As you were texting me earlier it might be that this information about blocking ports is not what they say.
Some Countries insist the ISP do this for "security reasons".
Some ISP do it for the reasons you suggest (money)
Unfortunately port 5060 can not be moved.
iChat is supposed to be able to use a Proxy - but I have heard little succes on this front.
It might be possible if you could find some one to explain public Proxies to you.
It might als be possble to create a Virtual Private Network VPN to your Buddy and then use Bonjour (if they are on a Mac) Another area I know exists but do not know very much about.
Having said that you may get some hep on both these options in
Getting Connected Discussions
Ralph