Premiere Elements is a video editor, so you're not going to get an output larger than 1920x1080. So the first thing I'd do is resize those photos to 1920x1080 or you're likely to overload the program. Even better if they're no larger than 1280x720, since that's the most efficient size to load to YouTube anyway.
Then start a Premiere Elements using the project setting for AVCHD Lite 720p30. And, before you add your photos to your project, go to Edit/Preferences/General and set the still image duration. Setting the still image duration to 1 frame will automatically load your animated slides in at 30 per second.
Or, in your case, since you want 40 frames to last 60 seconds -- you want each still photo to last 1.5 seconds, so set your Still Image Duration to 45 frames.
Since you're creating video for the web, you don't need to think in terms of PAL or NTSC. Just load the hi-def file to YouTube when you're done.
I completely agree with Steve, and especially on Scaling the Still Images in Photoshop, or Photoshop Elements, prior to Import. This article goes into more detail, and has steps for batch-processing an entire folder of Stills: http://forums.adobe.com/message/2200755#2200755
When I do Stop-Motion, I like to do a small test with a few of my Images first. I usually decide on between 3 - 10 frames, but that choice is based on the "look" that I want, with those particular Images. It just depends.
Steve make a great point, and I want to reinforce it - when you do decide on the Duration, that suits your purposes, be sure to set the Stills Default Duration, BEFORE you Import all of your Stills into the Project.
Good luck, and when you have uploaded to YouTube, please add a link to it, in this thread, so we can all see it.