What kind of timer? Just a countdown clock will tell you how much time is left and give an alarm when done.
A program timer can list steps and ingredients etc.
I use the one in Beersmith. It has a mash timer and a boil timer. For the boil timer it gives time left and time to the next step. It also lists all that is included in that step. Like: 15 min. 1oz Saaz, .5 oz Columbus, 1 tsp Irish Moss.
I have also added my wort chiller as a misc. item so it will appear in the timer to remind me to boil it for the last 15 minutes.