Some important questions first, how long had you worked there and how long ago were you fired? There is a time limit on launching a tribunal case and you cannot claim for wrongful or unfair dismissal if you have been employed under 12 months unless there is discrimination (as in legally defined discrimination).
It can be very lengthy and expensive. Do you have any legal expenses insurance, say on a home insurance policy?
You would have to get a company who agreed to take the matter on on a contingency fee basis and they are only likely to take such a case on if there is a very good chance of them succeeding.
If you do have a good case then it might be possible to get a settlement so that the case does not go to tribunal but this is impossible to know, especially on the limited information given.
I'd also ask as to the basis they fired you on.
ACAS might be able to give you further advice:
http://www.acas.org.u...x.aspx?articleid=1461