first, dont use dificul word to explain, i'm chilean, 17 years, and i know english but not all those technologic words...lol
well, i wanted to know what was Ping for, what does it mean in the game, and what is it matter on Soldat...
well, hope u answer, bye

"Ping" is the time it takes your computer to send a message to another and back again. Like a measure of how long it takes you to recieve mail you sent to yourself.

in miliseconds

if that didn't help here's a more simple version concerning games:

it's how fast your connection is to the server. If it's a small number (around less than 100) you have relatively good 'ping' or fast connection (that's when the dot at the top-right in soldat is small/green/transparent). when you have ping of 250 or over, i'd consider that a slow or bad connection (more orange). and if the dot is red and big, then leave the server, or get better connection.
so if you have dial-up, you might have pings of over 300 (i'm guessing). dsl/cable can go down to a ping of 33 - which is really good!

technical:
if you wanna compare to my good connection, you can open command prompt (start -> run -> cmd) and type "ping yahoo.com". it'll say a bunch of stuff and then shows your average connection. for me it's 38ms. the higher it is the slower your connection, the more the game will lag for you!

Yeah, that's pretty much it. Basically the less ping, the smoother a game runs, so you want to join servers with the smallest ping as possible (servers with low ping are closer to you so it cuts "time it takes your computer to send a message to another and back again") ;-)