Tuesday is almost always the day every single new release comes out. Any particular week's releases will be on Tuesday.

deepdiscountdvd and dvdempire and amazon are websites where I am happy to purchase DVDs, depending on price. Deep Discount is a little slow and has a higher chance of having packaging damage, but I've never had a problem with the actual discs. I've also purchased a handful of international DVDs, the web is pretty much the only way to do that for most people.