For me the key points are –
– Be very clear about labeling the content as sponsored
– Continue to produce your own content – don’t just re-package press releases from the sponsors
– Be honest in your reviews – no whitewashing please

I come to your site because I like a lot the software you review and your reviews generally match my experience using the stuff. As long as that remains true I’ll keep coming back.

If people want to pay you to leap the queue and get their products onto your site – congratulations! Just try not to review stuff that wouldn’t previously have made the cut…