When I was at Uni there were a couple of peeps with dictaphones and they used to put them on the lecturers podium. Not all the lecturers were happy with this though- suppose there's a data protection issue.
Also to be honest I think itll be a lot of extra work, listening back to the tapes in the evening.
Personally wouldn't bother unless you have a problem writing or something
hi! im just going into my final year and I used one in my lectures, most dont mind you using them. i find it a very useful way of adding more to my notes, i also annotate through out, find it helps if i listen to last week lecture or way to this weeks, keeps me up to date and jogs my useless memory! what year are you in? also do you university use blackboard? if so then ask if blackboard notes will be available to you before the lectures so that you can have a read through them and if need be do some reading before class. my tutors are very understanding esp as im a lone parent.