I created a new Asterisk wiki page: https://openwrt.org/inbox/new_asterisk
The old one is completely outdated an merely lists all the packages, which can be done using the package table.
Providing Asterisk configuration is tricky, since it highly depends on provider/hardware/country. I tried to provide as much generic information as possible, with lots of pointers to the official Asterisk wiki. At the end I provided examples for my provider, taken from a previous forum post.
Maybe it's better to split out provider-specific configs into separate pages - what do you think?
Stefan Koch already wrote an article about chan_lantiq which I link to in my article.