bind <key> <command>.

Binding can be done via the console in-game or by editing a .cfg file in your cstrike folder. To bind in the console a specific text to display replace <key> with a key which is not yet used for anything else in your game. I suggest using - or h. Then replace the <command> with:

say \"The Counter-Strike Community :: www.InTheHoleCS.net\".

Hit enter and then simply press the key you assigned. The message should appear automatically.

Example:
bind - say \"The Counter-Strike Community :: www.InTheHoleCS.net\">