+1 with netwolf. The lodestar with starlight live, or asi224MC camera for colour on sharpcap. There's also RisingTech cameras based on the same sensors which are cheaper and have their own software.
If you just want to have a quick look without buying another camera you could just use the DSLR for live viewing. Another IIS member Howie gets beautiful live shots, here's a link to one of his youtube demos:
https://www.youtube.com/watch?v=uG9ByXFDrEE
Just use any capture program, eg eos utilities (free), to dump single 15-30sec shots into a folder. While doing this astrotoaster stretches them and can stack multiple images if you want. Works like a charm. Astrotoaster uses the DeepSkyStacker engine, and with the newer 64bit version it works really well (not as fast as sharpcap though).