As you've probabaly discovered, Chilton and Haynes only have model-specific manuals for up to 1998 for the North American Accent - Chilton publishes an import car shop manual covering up to 2002 - It can be ordered on line for around $45 US
Another source that might be useful is Hyundai USA's on line shop manuals at
https://dcs.hyundaidealer.com/customer/index.jsp - Click on Technical Info and then enter the model and year - click on "shop" for the shop manual.
If for some reason the server isn't responding go to
http://www.hyundaiusa.com/, then click on "Owners" and "Parts and Accessories"
This is nowhere near as detailed as Haynes or Chilton but it gives you a lot of info on specs and troubleshooting.