How can I get CPU count and total RAM from the OS X command line?

You can get this from the system_profiler tool:

system_profiler SPHardwareDataType | grep "  Memory:"
system_profiler SPHardwareDataType | grep Cores:
system_profiler SPHardwareDataType | grep Processors:

or, if you want to go low-level, use sysctl:

sysctl hw.memsize
sysctl hw.ncpu

Or to capture the values in a script (credit: @bleater):

mem_size=$(sysctl -n hw.memsize)
cpus_virtual=$(sysctl -n hw.ncpu)

btw, there are a bunch of other interesting things you can get from sysctl. Try:

sysctl -a | grep cpu

to see a few of them

The following works in OS X Lion:

$ /usr/sbin/system_profiler SPHardwareDataType

Hardware:

    Hardware Overview:

      Model Name: iMac
      Model Identifier: iMac7,1
      Processor Name: Intel Core 2 Duo
      Processor Speed: 2.4 GHz
      Number of Processors: 1
      Total Number of Cores: 2
      L2 Cache: 4 MB
      Memory: 4 GB
      Bus Speed: 800 MHz

scorp@antani-mac:~$ hwprefs cpu_count
2
scorp@antani-mac:~$ hwprefs memory_size
4.00 GB