Embed videos
Looks like a different parameter is used now – start=<number of seconds> (see this blog and documentation).
Example:
<iframe width="420" height="315" frameborder="0" allowfullscreen
src="http://www.youtube.com/embed/Nc9xq-TVyHI?start=110&end=119"></iframe>
Direct links
For direct links, it is enough to simply replace # for &:
http://www.youtube.com/watch?v=Fk2bUvrv-Uc&t=2m30s