Although this software has been around for a bit, we've somehow managed never to get around to talking about it and were happy to get a reminder from Jason Landridge's recent Top Ten: WMWifiRouter. It's a dead-simple way to turn your Windows Mobile phone into a WiFi router. One touch of the button and your 3G connection gets shared over your phone's WiFi to be shared with surrounding devices. Actually, it can do a bit more than that, sharing connections over Bluetooth and USB too.
Setup is dead simple, support on their site is pretty darn comprehensive, and more features appear to be on the way. Just be aware, though, your carrier probably would consider WMWifiRouter to be tethering, so if you're not on one of those plans they'll probably come after you if you use it a lot. Go on and download the trial or send 'em your 19.99 Euro.