Did that three weeks ago.

There's a bus about once an hour that goes to the Place D'Europe from where you can pick up a tram or bus to anywhere else in the city. Airport bus is operated by Herault Transport.

Shuttle price: single: 4.90 euros (possibility of buying notebooks of 10 ways to preferential rate) and 5.40 euros (with TAM option) (TAM option is a transfer to bus or tram at the end of the run)

That from the Montpellier Airport website http://www.montpellier.aeroport.fr

A taxi into town is about €20.

City bus/tram information at http://www.montpellier-agglo.com/tam

Hope that helps.

Cubsur,
Many thanks for the information, costs and links.