Well it looks like PHP 4 support will be ending soon Great news for all web hosts out there supporting multiple php versions to please everyone. It's also great for developers wanting to use php5 functionality that just isn't there in php4. Or you can visit http://php.net/
I already forgot about php 4... aha, though some things were shorter to do, but im still getting used to some things i used to do in php four which i have to do a tad differently now. But I don't miss 4 one bit...
You right, many still only support php4 so I wouldnt be supprised if there is a period where both are supported for a few years until php4 is phaised out.
I know we (Hawk Host) supports both PHP4 and PHP5 and most other hosts I know of who know what they're doing support both or just PHP5.
My reseller host is still only supporting PHP 5 as an experimental thing - not fully deployed yet. They will, at some point, switch over completely to PHP 5 (with PHP 5 being the default handler for .php files) I think a lot of hosts want to leave the transition period as long as possible, for clients to iron out any problems with PHP 4 code.
I am so used to using OOP in PHP 5 that I occasionally get annoyed when I am not able to chain methods and do other stuff like that on my free webhost . ~ Thomas