Not a link, but just three of the top data modeling tools (in my opinion):
1. Sybase PowerDesigner. (Yes, it supports Oracle 10g.)
2. Embarcadero ER Studio.
3. Computer Associates ER/Win.
All have personal and collaborative editions. The collaborative editions require a repository for storing meta data centrally, similar to how Oracle Designer used to do it.
You don't have to get PowerDesigner from Sybase. You can get the same product from Quest software, the people who sell Toad. It's the same product, so you really just need to decide which group you want to buy support from and see if you can get them to offer discounts on their other products you might buy at the same time.
It comes with a repository if you want to spend the $$ and tech support is good as well and there is a dedicated newsgoup for the product on Sybase's website with knowledgable people. The developer who created the product is still on the team.