With an ever increasing number of brands launching iphone apps, here is a list of the ones that we know of. We're not going to put reviews of each of these, as that would increase this post to mammoth proportions, but the amount of information and interactivty varies greatly from brand to brand. Some are very minimalist and only focus on one watch, whilst others do regular updates from the brand's website, with the Rolex one being particularly useful.
1. Bell & Ross
2. Breitling B01
3. David Yurman Timepieces
5. Dior Chiffre Rouge
7. Hermès Grandes Heures
9. Jaeger Le-Coultre
10. A.Lange & Soehne Zeitwerk
11. Piaget Polo Forty Five
16. Stepan Sarpaneva
18. TAG Monaco V4
19. Van Cleef & Arpels Charm watch
And the final one, which is not from a brand, is Fondation de la Haute Horlogerie
Happy downloading, and please tell us if there are any that we've missed.
18.1.2010 additions - Thanks to The Watch Lounge for Red8World info, @nickorloff for Vogard, and @Felixosaurus for Hermès.