SE-NSE Forums:

As some of you probably know, the C510, W705, W715 and W395 have been released quite recently. Just like with every other newly-released phone, SE has made several phone UI demo sites available. Yep, that means you can try out these phones on-line before eventually buying them. And no, I didn’t mean to imply anything with that last sentence…

Here are the links:
C510 demo
W395 demo
W705 demo

The W715 demo is the same as the W705 one.