Newbie question: precise requirements to enable MS SQL connection

Hi there! I'm terribly sorry for this newbie question, but the information I've dug up regarding this topic is woefully incomplete and patchy. I'd like to know the precise requirements for establishing a connection between a Linux box running Apache / PHP4 b2 and MS SQL Server running on an NT 4.0 machine. -Which version of SQL Server can I connect to? I'm currently running SQL Server 7.0, which seems to be completely unreachable by PHP... -Which version of RedHat Linux should I be running? I'm currently running redhat 6.0, but I've read at least 1 post stating this won't work, and I should revert to RedHat 5.0 or less... -Which middleware driver should I use? SybaseCT seems to be the popular choice, but I've also heard mutterings about OpenLinkSW, and the one designed for FreeBSD (can't remember it's name...). -Is PHP 4 even ready for any of this? I've read at least 1 post stating there was difficulty in establishing an ODBC connection through PHP 4. Should I revert to PHP 3? Sorry once again for all these newbie questions. I'm quite lost and I would greatly appreciate any direction you can provide... Thanks in advance, Alex K.