As might be abundantly obvious, I use and love the Xamarin tools for mobile development - mostly MonoTouch, which I've used for all my apps, but also Mono for Android. They are fantastic tools, backed up by fantastic support and an amazing community.
Xamarin are now offering 5% off for anyone buying thru their referral program, so if you are considering buying one - or both - of them, hit the links below and get some money off!
I also have some blog posts cooking for the app I've been working on lately, and some plans for a new one and some tweaks on two old ones. I just have to find the time to write them!
[disclaimer: yes, I make a small amount if you buy using the link, so be both win!]