In response to a question to Orange, they replied as below. The odd thing is that on following the link, their site says that FROYO has been released and tells you to install Kies etc in order to upgrade. I just don't know what to believe!
Hello Peter
Thank you for your email regarding your Samsung Galaxy S i9000 handset. 
I am sorry to learn that you are unaware of our process regarding firmware updates for Orange phones. Please accept my apologies for any inconvenience this has caused. 
I would like to advise that Orange customers are not able to obtain firmware updates direct from Samsung themselves, this is due to the Orange branding that you have on your phone that allows you to use this on our network. 
Please find below a link to our website where you are able to check in the future if an update via Orange has been released. 
http://www2.orange.co.uk/servlet/Sa...96364420640&product=Feature&t=Product&tabid=1
Be aware that your handset may not be available on the listings until if or when an update is released.
When a new update is made available by a handset manufacturer they will pass a version of this to Orange so that we can run the required tests to confirm that this update they have released will co-exist with the Orange branding that you are required to use on your phone. 
It is possible that the new update that is released may not co-exist with the Orange branding and thus we will not be able to release the update for the Samsung Galaxy S i9000, if they can not co-exist and we were to release this to your phone, this could effectively be detrimental to your handset and Orange will not process for this reason. 
If the update version can not co-exist with the Orange branding then we will wait for Samsung to release a new update to which we will restart the testing process accordingly. 
Be aware that it is not possible to advise of any estimated timescale for the testing of this update by Orange, furthermore, we can not guarantee that an update will be released at all regarding the Samsung Galaxy S i9000 as the updates that could be released may never work alongside the Orange branding on the phone. 
Because some of this information is speculative and based on situations regarding the testing of updates that may or may not ever be released by Samsung and the time it takes to complete the testing of the new updates, please accept my sincere apologies that we can not be more specific regarding your query. 
As with the current Android update it has been released via an Over-The-Air format, this may be the situation for the the next available update, but this method we will not be able to confirm until the update is valid for Orange UK handset users when it has been released. 
Please be advised that the answers to many common queries can be found in the Frequently Asked Questions section in the Help and Support option on the Home page of our website. 
Mobile Phones | Broadband & Mobile Broadband UK Deals | Free Web Email | Orange.co.uk 
I trust this information clarifies your query. 
Kind regards