Handy way of running PHP on a USB drive…the most obvious being demonstrating your wares to a potential client on their computer , but the possibilities should be obvious to any PHP heads who in general I find are quite an inventive bunch. In the past I have produced AMP CD-R’s , e.g. Apache/MySQL/PHP installation running from a CD-R , a USB flash drive install is even easier since we don’t have to worry about non-writable media, the point of this article by the way is to provide a portable system with no hard-coding of drive paths etc. Link.
PHP on USB