Depending on the used mod a Half-Life server will end the current map and wait some time until it starts loading the next map. Usually players can view the scoreboard while this time. The time period a server waits is configurable and can be different on every server while players have no way of knowing when the loading of the next map will finally start. xLoadCountdown is an AMX Mod X plugin that closes this gap by showing a countdown during this time period until the map loading will start.
xLoadCountdown source and compiled plugin can be downloaded from the first post of the official xLoadCountdown thread: