Welcome to TPF, New Here! You've chosen a difficult aspect of photography to tackle, as the low light, rapid movement, and all-over-the-friggin'-place white balance makes for challenging work, but you've done a nice job. I'm quite surprised to see such noise-free images out of a D3000; what ISO were you shooting at?
1. Godo overall exposure, nice moment. I would to have seen the whole guitar, but that may not have been an option.
2. Exposure is spot on here as well, and both are nice monochrome conversions. Unfortunately you've cropped away a good deal of his left arm which IMO hurts the image somewhat, but there may have been no choice.
3. Good colours! it's hard to tell, but the image seems to lean slightly down to the left. These 'contemplative' shots are nice, but so are 'connection' shots. I hope you got some where he's looking at the audience.
4. Great shot! I see just a bit of motion blur in his right hand, but that doesn't hurt at all. The image does lean rather badly to the right however. I'd level it and crop the bottom off just to get rid of that aluminum stage panel.
Overall, a really solid effort - I'd like to see what you could do with a D4s & 70-200 f2.8! Looking forward to seeing more.
