Mouseovers
 

I want to use mouseovers to hide my sponsor code code in the link. Will any LL not list my site for this?

As far as I know as long as you are using the root url to the sponser and not some crazy crap you should be ok. IE. On mouse over should read http://www.sponsersite.com (hiding your ref) is ok.
On mouse over "Hey get free porn here" is not ok. The surfer should have some idea where you are going to send them and not some shot in the dark.

I second juggernaut.

Just be sure to check the rules for each list before you submit. Usually they'll let you know if it's not acceptable. :)