http://www.lmgtfy.com/?q=broken+toe
Summary: if severe break (big toe, sticking out at angle, intense pain, blood trapped under toenail) you need a visit to A&E. Particularly in the last case, this can be the difference between keeping and losing the toenail.
Otherwise (from NHS.co.uk):
* Put a piece of cotton wool or gauze in between your injured toe and the one next to it and tape the two toes together with a plaster. The healthy toe will act as a splint.
* Keep your foot raised for as long as possible, for example by resting it on cushions. This will help reduce the swelling and pain.
* Hold an ice pack (try frozen peas wrapped in a tea towel) to the toe for 15-20 minutes every one to two hours for the first couple of days.
* Rest the toe by not walking or standing for too long, and not putting weight on the toe.
* Take over-the-counter painkillers such as ibuprofen to relieve the pain.
* Wear sturdy shoes that do not squash or bend the toe.