I was hoping to rewrite the Duskblade for Pathfinder, but I wanted to know if there are specific rules I can find on converting D&D 3.x classes to Pathfinder. Are there?
Yes, but they require quite a lot of experience with the games in question. But there are a depressing number of conversations here. Unfortunately there's a whole book that attempts this discussion -- your mileage may vary. Needing to do this level of homebrew is likely a sign of insufficient system mastery, a love of graven idols, and a need for a better system that supports your requirements.
You also need to have a thorough knowledge of the literature: what do people involved in that system's community think about various aspects of the rules as they relate to mechanisms of your class. Why do they think that way? What are the settled issues? What are the controversial issues? Why are they controversial? All of this discussion is a record of the knowledge and mistakes people have made so you don't have to. Given that you didn't bother to google (or your searches failed to find results) for this in the first place, I would recommend against the practice until you've improved your searching skills. To quote the academic reasoning for lit reviews:
It makes no sense to start a research project without knowing what work has already been done by others. Wouldn't it be embarrassing to unknowingly repeat what others have already done?
There's quite a lot of discussion around current efforts to convert classes, especially with regards to the duskblade. With that said, using and choosing conversions requires a deep system mastery and the expertise that comes of having played a few campaigns with different players to get a sense of how and in what direction conversion choice will break. Layering complexity on top of custom homebrew is severely disrecommended.
Gaining system mastery, and more importantly, expertise in GMing is critical before hacking rules. Once you've run a campaign and have the necessary chops for building characters out to level 20 with an understanding of what choices are made at every level and why, with complex prestige class choices, then start poking your head into the murky world of homebrew classes. Duskblades (unlike binders) are not sufficiently original that they cannot be reproduced.