You can get the head and the tail by pattern matching. Lets say you have a function that takes a list:
myfunction list = -- do something here
go = myfuction [1,4,2,6]
... you can write the "list" bit of the function as (x:xs), where x is the head, or first element, of the list, and xs is the tail, or the rest of the list:
myfunction (x:xs) = -- do something here
then you can call myfunction on xs, and compare that to x, to give the result.
This is recursive: the function calls itself over and over again, until at some point it's going to execute "myfuction []" or "myfunction [6]", which is easy to handle, for example by adding the definition:
myfunction [a] = -- the value of myfunction given a
Go here for a really great tutorial:
http://www.cs.nott.ac.uk/~gmh/book.html
Recursive functions are in slides, number 6, but the tutorials are really great: just start from 1 and work your way through.