It will take some training and some time to learn the style needed to develop maintainable code.
Coming from Java/C#/C++, you probably have a good idea of good software architecture. Now you just need to learn the peculiarities of LabView and the common pitfalls.
For the basics, National Instruments offers training courses. See if your new employer can send you to a Basics I/II class to get your feet wet. They offer some online classes as well. Following classes, you can sign up to take tests for certification.
Get an evaluation copy of Labview from National Instruments; they have a well maintained help file that you can dive right into, with example code included. Look at "Getting Started" and "LabVIEW Environment". You should be able to jump right in and become familiar with the dev environment pretty quickly.
LabVIEW, being graphical is nice, but don't throw out your best practices from an application design point of view. It is common to end up with code looking like rainbow sphaghetti, or code that stretches several screens wide. Use subvi's and keep each vi with a specific purpose and function.
The official NI support forums and knowledgebase are probably the best resources out there at the moment.
Unofficial sites like Tutorials in G have a subset of the information found on the official site and documentation, but still may be useful for cross reference if you get stuck.
Edit: Basics I/II are designed to be accessible to users without prior software development experience. Depending on how you feel after using the evaluation version, you may be able to move directly into Intermediate I/II. NI has the course outlines available on their website as well, so you know what you're going to cover in each.