For the most part, you can find everything in the Husserl Archives online, but these websites are hard to find. Here is a list of websites that I regular use as part of my research. NB: I am still looking for a database of all the photos in the Archive. If you have any information, please send it my way.
Husserl Archives Leuven — This is the official website for the Archive. You will find contact info as well as the Digital Husserl project, where everything so far digitized is posted, minus photos (despite the documents’ link that has a photo but doesn’t link to anything but a “zero results” page). An up-to-date list of Husserliana volumes can be found here.
The Husserl Page — An extremely information dense website by Dr. Bob Sandmeyer, who I believe is at the University of Kentucky. Its aim is “First, this site provides a series of originally created bibliographic and informational pages relevant for research into Husserl's philosophy and its development. Second, this site seeks to supply an exhaustive and up-to-date listing of externally produced Internet sites relevant for research into the life and philosophy of Edmund Husserl.” It isn’t entirely up-to-date but nevertheless it is great.
The Open Commons of Phenomenology — Has lists of complete works and secondary literature on many phenomenologists. My main use of the website is to access pfds and TOC of the Husserliana volumes.
Husserl.net — I recently found this website (in fact finding it is what made me think to write this post) and it allows you to do a keyword search through the entirety of the Husserliana. It also gives the information about English translations, if available. The website is ran by Dr. Jeff Yoshimi.
Glossary-Guide for Translating Husserl — while a bit more specialized, this website is a great help with translating Husserl.
Husserl-Database — Unfortunately this appears to be no longer in operation.