In French, compound tenses are formed with the help of auxiliary 'avoir' or 'être'. So French verbs are classified by which auxiliary verb they take (they are used with one and the same auxiliary in all the compound tenses).
Well, most of the verbs use 'avoir', and the short list of those requiring 'être' is easy to remember:
All the verbs are intransitive (can't take direct object) denoting some kind of movement.
NB! Derivatives of these verbs also use 'être'.
If you find it difficult to remember the verbs, here's a mnemonics for you (Dr and Mrs Vandertramp):
Though it includes some derivatives, the mnemonics is rather helpful, I think. (If you know a better one - please, share :)
And, of course, all pronominal verbs use être (+ 's' in the end (for Pl))
To check your grip on être verbs click here.