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It has recently been mooted that micro-satellites could be propelled to nearby stars through the use of powerful, ground based laser systems. However, given that light has no mass, I don't know how to calculate the force exerted by a laser on an object and Google has been relatively little help.

Consequently, is there an easy way to calculate the force exerted on an object by a laser given the power, frequency, distance, albedo of the impacted material etc.

ScottishTapWater
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Relativistic energy is:$$E^2 = (m_0c^2)^2 + (pc)^2,$$ For light, rest mass is obviously $0$, so $E^2 = (pc)^2$ and $E = pc$. You can substitute $E = hf$ here, and that gives you the momentum of light. Combine this with the number of emitted photons per second from a LASER, and Using this and some simple maths you should be able to work out the rest.