Hi m12318 - Welcome to WebmasterWorld :)
Remember to read Paynt's Welcome Thread [webmasterworld.com].
Now for your questions:
>have you tried..
Well, it depends on the type of site and content you have. You have to sit down and do a little math. If your site can handle paying for traffic and you have a worldwide audience - mainly Europe - I would recommend trying a few pages and see how they perform. If the ROI is there, you can add more pages and see where it goes.
Remember that FAST's reach in the US is mainly through Lycos and the search volume here is limited. However targetting Europe, specially Scandinavia, it can be very rewarding as supposed to waiting for FAST to pick up your site.
Yes, you can edit your URL as long as it within the same domain.
Well, I go through PositionTech and their sevices seems ok to me. I've had a few troubles going through Lycos, but maybe that's just me :)
Good luck, and do ask again, but remember to use the Site Search [searchengineworld.com] on top of the page. There's a wealth of information here.