This might just be me and my uptight British ways ;-), but I'm not going to disclose my salary. I'm pretty happy with it though.
From my fairly recent experience of job-hunting (in London), having the certification didn't really make any difference. Some employers used it as a quick way to filter out applicants, and it's something that they liked applicants to have, but no more than that. Experience is more important.
One thing that I think does have a bearing on the sorts of salaries you can command is the size of the environments you've been working in, so you'd probably command a bit more money if you have a few years' experience as a DBA in a large investment bank with a complex setup than if you've only ever worked in a small enterprise with just a couple of small databases, even if you ran the whole department on your own.
It's certainly not a bad thing to do to go for the certification, but you may not see much immediate change in your salary because of it, that's all.