Most popular place to meet Heroes of Might and Magic III players is GameRanger. GameRanger is a free software. GameRanger offers features like profiles, friends lists, instant messaging, rooms. Most players are online from 4pm to 10pm GMT, however you can find players at other time too.
Games for rating at GameRanger
At GameRanger room's title mention "WCL" so people will know that you wish to report game result at WCL and get rating points. In general, WCL players are more reliable and more skilled than "unknown" players
Which version of Heroes of Might and Magic III do players need?
80% games go on Shadow of Death (SOD) (versions 3.2 and 4.0). These versions also are compatible with 1.4 (Restoration of Erathia; patch needed) and 2.2 (Armageddon Blade; patch needed). Around 20% of games go at HoMM3 Tournament Edition (TE) or HoMM3 World Tournament (WT), which are non-official mods made for balanced multiplayer games.
If you have version 3.0 or 3.1, then you may download patched heroes3.exe file from HERE
How is it possible to know my version of Heroes of Might and Magic III?
There are 2 options. You can check version in heroes3.exe file properties in Explorer. Right click at this file and select Properties -> Version; version looks like 126.96.36.199 or 188.8.131.52. File heroes3.exe is located normally at c:\program files\3DO\Heroes\. Second option to determine your version is to press F4 key in game, so game will switch to "window" mode with Menu. In Menu select Help -> About item. Game will not switch to window-mode if screen color quality is 32-bit (you will need to change it to 16-bit).
Average player search time at Gameranger
For skilled and known players: 5-20 minutes; for novice players: up to 1 hour.
How to determine is player skilled or not?
Novice players don't have patience. If opponent's turn takes more than 3-5 minutes, then novice player is bored, starts to talk much in game's chat and disturbs from game. Novice player usually does not know rules, does not have rating at any league and has very limited time for game (1-2 hours). Novice players often play without any rules and with time limit 1-2 minutes/turn
Why experienced players avoid playing with novice players? Novice players often quit at the middle of the game, sometimes even without notice
Novice players often break rules (either occasionally or intentionally)
New players in 95% cases do not know game well, so it's simply not interesting to play with them
How much time do I need for game?
Usually you will need half-hour for searching player and starting game plus 4-7 hours for game (1 vs 1), 9-14 hours for game (2 vs 2)
I wish you good luck in games! Enjoy!