There are 25 in total. >1.1 Digital Watch 1.2 Calculator 1.3 Memo Pad 1.4 Pedometer 1.5 Pokémon List 1.6 Friendship Checker 1.7 Dowsing Machine 1.8 Berry Searcher 1.9 Day Care Checker 1.10 Pokémon History 1.11 Counter 1.12 Analog Watch 1.13 Marking Map 1.14 Link Searcher 1.15 Coin Flip 1.16 Move Tester 1.17 Calendar 1.18 Dot Artist 1.19 Roulette 1.20 Trainer Counter 1.21 Kitchen Timer 1.22 Color Changer 1.23 Matchup Checker 1.24 Stopwatch 1.25 Alarm clock
Bulbapedia - Poketch
In Diamond, Pearl and Platinum there are 25 available apps, four of which are included with the Pokétch.
For a full list of all the Pokétch apps, a detailed explanation and the location of each app click here.
Hope I helped :)
There are a total of 25 poketch apps that you can recieve.
source- http://www.serebii.net/diamondpearl/poketch.shtml
