what operating system should i use to install LAMP
Try the PCLinuxOS distro (www.pclinuxos.com). I recommend downloading the Gnome Zen Mini, or the KDE Mimime ISO. These two remasters of PCLOS have minimal software included in the ISO file, thus are best for setting up a LAMP server. Once you install, and update your OS through Synaptic Package Manager, search for 'task LAMP' (no quotes); select it and the task script will download all necessary packages to run a LAMP server. Afterward, it's a matter of configuring the respective servers. Webmin is an excellent tool for configuring and maintaining a LAMP server. Webmin is available in the PCLOS repositories and can be installed with Synaptic.
Another option is installing a Business Enterprise Linux (BEL) server available through Ondisk.com (http://on-disk.com/product_info.php/products_id/438). The BEL Project site is down right now, I don't know why, so you need to download through another site. Simply install the ISO image and you have a nearly instant LAMP server with Webmin as the default admin tool.