I would read a few short tutorials on JavaScript before jumping into jQuery. It is important to understand things like dictionaries, as nearly every jQuery UI component requires you to pass a dictionary of arguments. Working with jQuery is much different than working with regular JavaScript, so don't feel like you need to be a JS expert to use jQuery, as jQuery is almost a language on its own.
The important thing to remember with using JavaScript is to terminate every line with a semi-colon (;), even though this is not a requirement, you will save yourself hours of debugging by just doing it. Another thing is to never declare a variable like you do in Python. Always declare your variables using: "var myvar = 1;" The key component being the "var" keyword. If you forget to add that keyword to the beginning, the variable you declare will be available globally, and this can cause a lot of unexpected problems. As for jqgrid, it is part of plugin-wiki, I believe. However, jqgrid itself is a beast. If you are anything like me, you will find yourself writing a full page of just initialization arguments. I would work to become proficient in jQuery, jQuery UI, and web2py long before you start playing with jqgrid, as there is a lot of stuff you have to figure out in order to get everything working properly. To avoid frustration, it would help to already know how all the individual pieces work before trying to integrate them.
