Recently, I setup a Dell server and it came with OpenManage Systems Management software to setup RAID, etc. Does anyone know if there is an open source software similar to that or along those lines I can use for any server setup?
Every brandname server has it's own set of hardware configuration and monitoring software. If you're using a single brand across the entire datacentre, just go for what the vendor provides.
Otherwise, you'd need something like Nagios plugging into OMSA and it's likes on other hardware for monitoring, and as for management of the hardware, I'm afraid you'll have to manage sets of different hosts separately.
For asset management there are packages like GLPI, which is quite nice after you hack it up a bit