Aside from all the pioneering DIYers out there, we've already found one retail accessory from Nike themselves that lets you use the Nike + iPod kit with any shoe, but now Marware has joined the race with their Sportsuit Sensor+ (looks like the '+' is becoming a hot new accessory to accessory names). This tiny pouch is form-fitted for the sensor and can attach to any shoe's laces via velcro. As icing on the cake, the pouch also has room to store the wireless receiver when not in use, and it protects the sensor "from all the elements that serious runners encounter." I guess they could've said 'it's weatherproof,' but that doesn't have the same flair.
The Sportsuit Sensor+ is a mere $10 and is available for pre-order now.