Spam Databases

I have found out recently that my Yahoo email account and my business accounts have shown up on www.dnsstuff.com and flagged listed on SPAM DATABASES.

I have just switched to using DELTA WEBHOSTING for my freelance work, and it seems like ever since then I have been using them I have been moved from server to server and now I’ve been black listed on a SPAM DATABASE.

My yahoo account has been blacklisted on 3 SPAM DATABASES.

How does this happen and how can I get my emails white listed?

I’m especially concerned about my Freelance Email. I assume this is a new issue because of my DeltaWebhosting server. If I change server space will I be white listed on the SPAM Datatbase sites.

I don’t know much about this stuff so if anyone can fill me in that would be awesome.

Thanks in advance.