In This work we present a linear programming formulation for the routing problem in optical burst switching networks (OBS). Unlike in conventional wavelength routed networks, in an OBS network (light)paths are allowed to clash. One should, however, try to minimize the number of clashes as each of them can potentially cause a burst occassionally to be blocked. Thus, by choosing the paths and wavelength channels carefully one can decrease the blocking probability and also improve fairness among the different connections. In This work we propose an OBS-aware routing policy, which is shown to improve the overall performance in terms of blocking probability and fairness.