For MC 1.1 Vanilla server.

This handy little mod does what it says on the tin: it customizes the vanilla Minecraft server with several new features, such as a new layout, commands, a logon message, and tons of toggled settings. Includes:
Villages spawn in more places, like tundra, forest, and taiga, but are still kept out of mountains and swamps (basically a throwback to the prerelease where they spawned everywhere, but with more restrictions),
No more yellow text in logon and logoff notifications,
Customizeable logon message-of-the-day and toggleable "show other people who are on" thing, "Connected players: Steve, Notch" etc.,
More commands (/day, /night, /offline, /online) (whether or not they are allowed is toggleable)
Changed /toggledownfall command to /weather
Enabled inter-dimensional teleportation
Warns ops when the server lags (can be changed to show normal players as well or not at all),
Hardcore mode, toggleable through commands and the customserv.properties file,
New world options (Megaforest and Winterfrost, replace DEFAULT with either FOREST or WINTERFROST),
and, best of all, shows ops why people disconnected (can be changed to show normal players as well or not at all.

To install, download the Minecraft 1.1 server jar at minecraft.net and use your favorite compression utility to open it, and simply drag over the classes in the mod into the server .jar

Note about Winterfrost biome: Downfall renders as rain, but acts like snow. Probably clientside, I may release a patch.

Enjoy!