The leading professional services firms all offer some sort of exposure in your first year. The majority offer open days or events that will allow you to get a feel of the sort of work that is undertaken in these firms and what career opportunities they offer for both students and graduates. Mosr are relativley short in nature - between 1-3 days.
Be aware that the most professional services firms ask you to complete online tests. You have to pass these before they even look at your application. Its critical therefore to gain some practice before you take them. Obtain practice papers and advice HERE