If you use a VOIP provider for PSTN calls, you will be able to relate to the frustratingly boring caller ID names that get passed down to you. Very infrequently do I get anything better than a city name. Even if you have a direct PSTN connection into Asterisk, you may find the caller ID names from cell phone users (maybe just about everyone that calls you) are less than precise. Here's a solution.
We want to store alternative names in some kind of database that Asterisk can access when a call comes in. AstDB is perfect for this. We also want to leave things unchanged if we haven't manually stored a name for this number. The following will do the trick:
Set(CALLERID(name)=${IF(${DB_EXISTS(cid/${CALLERID(num)})}?${DB(cid/${CALLERID(num)})}:${CALLERID(name)})})
Now, we just need a way to update the database with names. At first I had grandiose ideas of an AJAX-enabled website that shows you the last few CDR records and lets you edit the names with a spiffy in-place editor. You could still accomplish it, but in the end I came up with a much simpler if less elegant solution. At least, it's simpler if you use the terminal all the time like I do. Put this script in your path:
#! /bin/sh
# usage: $0 number "name"
user=`username`
host=falcon
exec ssh $host asterisk -rx \'database put cid \"$1\" \"$2\"\'
Combine this with jabber notification as I've discussed before, and a little cut & paste from your jabber window, and updating names is cake.