osmitter is a wonderful tool for OpenStreetMap users — it enables your mobile twitter client to add POIs (and some other kinds of data) into OSM database!
You add a place by describing it with key=value tags which is a common way for OSM people. Tags for almost everything you want you can find at OpenStreetMap wiki.
Crazy? Try it!
add any combination of key=value pairs to the node — extremely handy to use with gps-enabled phones.
Current schema doesn’t validate points added with this tool — so, you can easily add a duplicate. We’re going to add a simple validation in the nearest future.