Recently, I finally lashed out and bought an FXS-100 module for my A400P card, and yesterday it arrived, so I can now plug in a cordless phone. My poor main Linux box now has more cables going into it than you can poke a stick at, and the closet it's in is getting completely out of control. Oh well.
Said module works fine, installation was painless, configuration equally so. I managed to do it all whilst being slightly tipsy from the pub last night, and no-one got hurt. It's so cool getting a dial tone from a Linux box.
There's a few caller-ID issues to resolve for internal calls, but other than that, it's great to be able to call Australia from the couch for 10 cents, rather than sitting on the floor near an Ethernet wall jack.