Navigate to the folder: 'program files\steam\steamapps\common\call of duty modern warfare 2\players' and open the file config_mp.cfg
Change scoresping_interval from 100 to 20, and maxbars from 4 to 10 (10 is the max).
This means that each of the 10 bars represents 20ms, with full green being 20ms or lower, and 1 red being 200ms or higher.
WHAT IT LOOKS LIKE:
The sad truth? You might wanna pound a few beers before you read this:
The host is immediately obvious, he's the guy with 0-20 ping (full green).
I usually connect with about 101-200+ms.
Most people are connected at 200+ms (3 or less bars on normal cfg settings).
On regular cfg settings, 4 bars means up to 0-100 ping, 3 bars 101-200, 2 bars 201-300, 1 bar is 301+.