I have used my windows phone 7 for last 2 years and yesterday placed an order for Nokia Lumia 920 (phone 8). How can I transfer all of my apps to my new phone? (Is there a thing like if I sign in using my live account, all my apps are installed by itself?)
To answer your questions (I already mad the switch to the Lumia 920(:
All apps I tested could be installed. At least one (Xing) had problems at the time this post was written. Microsoft told apps will run, but it seems there are some edge cases where apps could do things on WP7 that do not work on WP8.
There is no Auto install. When logging on to https://www.windowsphone.com/ you should be able to send the apps to your new phone using https://www.windowsphone.com/en-us/my/purchase-history
Edit: I had written that Photosynth doesn't work on WP8. That is by design as the functionality is now provided native through WP8.