How can I find out if my server has IPMI of some sort?

If it's Red Hat, just do rpm -qa|grep ipmi. OpenIPMI would be the most likely install, or one of the proprietary ones (like hpIPMI). There should be an equivalent command on .deb systems and Solaris boxes as well.

From FreeIPMI's FAQ section: 7. Does my system support IPMI?.

Does my system support IPMI?

Unfortunately, there are no universally defined mechanisms for determining if a system supports IPMI via Inband communication. Assuming IPMI is set up correctly for over LAN communication, a fairly reliable mechanism exists out-of-band. Here are some suggestions.

1. FreeIPMI’s ipmi-locate can be used to determine if IPMI can be found on your system. Users are cautioned though, the failure to discover IPMI via ipmi-locate is not sufficient to disprove that IPMI exists on your system. Your system may not publish such information or may expect clients to communicate at default locations.

2. dmidecode may be similarly used to probe for devices that support IPMI on your system. You may grep for IPMI or specify the IPMI DMI type on the command line.

    # > dmidecode --type 38
    # dmidecode 2.10 SMBIOS 2.5 present.
   
    Handle 0x0049, DMI type 38, 18 bytes IPMI Device Information
            Interface Type: KCS (Keyboard Control Style)
            Specification Version: 2.0
            I2C Slave Address: 0x10
            NV Storage Device: Not Present
            Base Address: 0x0000000000000CA2 (I/O)
            Register Spacing: Successive Byte Boundaries
   

3. FreeIPMI’s ipmi-ping can be used to see if a machine has an IPMI service at a specific host/IP address. For more wide scale IPMI discovery, the ipmi-detectd daemon and ipmi-detect tool can be used.

Again, the failure to find an IPMI supported device is not sufficient to show lack of IPMI support.

Ultimately, some amount of information from product documents or trial and error may be necessary to determine if IPMI is supported on your system.