Mandiant Memoryze is a free tool that can, among other things:

"# enumerate all running processes (including those hidden by rootkits). For each process, Memoryze can:

* report all open handles in a process (for example, all files, registry keys, etc.).
* list the virtual address space of a given process including:
o displaying all loaded DLLs.
o displaying all allocated portions of the heap and execution stack.
* list all network sockets that the process has open, including any hidden by rootkits.
* output all strings in memory on a per process basis.

# identify all drivers loaded in memory, including those hidden by rootkits.

Mandiant's site has additional information about the utility.