Lots of advice in different places, and many many complaints on the forums of Mozilla, Google and malware-removal sites. Ignore anything that involves paying for a miracle removal tool, and avoid anything with "Yoo" in the title (YooCare, YooSecurity).
The Google Chrome forum thread (13 pages long at last count) has a post from someone from Delta Search Support Department offering to help with the removal but no-one seems to have taken her up on the offer ...
The best removal advice is probably HERE, on one of the Microsoft forums.
Hmm, another delta search viticm
Can someone tell me what's the difference between delta search and babylon search?