Well that is a big question. Since you use a computer to access iTelescope.Net, then you should use a PC planetarium simulation or application, to display to you what is in the skies above the observatories world wide at anytime of night. We recommend Stellarium (free), Starry Night or TheSkyX.
It also helps to have an idea of what you would like to image, and we suggest Google Sky to help you find what objects you can image generally look like. Specifically, clicking the "Backyard Astronomy" link at the bottom is a good place to start.
Keep in mind that many of the images on Google Sky are taken with telescopes orbiting the planet, and therefor not shooting through Earth's atmosphere. They are also processed by professional astrophotographers in most cases, so the images you gather and process may appear slightly different or have slightly less details than some of those present on Google Sky.
See our Video Tutorials for lots of great information to get you started with Stellarium and our Launchpad.