The world of Linux audio can be intimidating for the beginner. You won't find it mentioned much in the big audio magazines. You can go to the sites for the various applications, but, as with many fields, you need some more general guides to show you what is possible. These are some of the sites that have helped me along the way.
Linux Musicians is a friendly forum where I've found lots of help and tried to provide it when I can too. They have a pretty good wiki where I have been contributing to a hardware matrix of compatible gear. There are other sites that try to list what works on Linux, but I found them limited when trying to work out how well supported an item is and how useful it is for non-trivial recording. They also provide a planet that gives an aggregated feed from various relevant blogs. I'm honoured that this blog has just been added. I recommend subscribing to get a good overview of what is going on.
I don't remember where I heard about it, but when the Open Source Musician podcast kicked off I was listening from the start. There has been some great stuff on there, although it's been appearing less frequently recently. They run some 'tunestorm' projects where listeners contribute tracks on a given theme. I really should try to take part in one of those.
One of the longest running writers on the topic of Linux audio is Dave Phillips who has written loads of great articles for Linux Journal. Unfortunately the latest ones will only be available to subscribers, but there is a great archive there that I recommend checking out.
Some Linux purists will prefer to use a mailing list such as Linux Audio Users. I do look in the archives now and again to see what is happening, but I don't have the time to keep up with a busy mailing list these days.
The FLOSS Manuals book on Ardour is worth a read. I ought to read it again and make some notes on things that could make my life easier. They have other manuals on other audio topics that I need to look at.
There are some IRC channels that may be good places to seek help, but I've not used them so much. Another good place is Youtube where you can find demonstrations of various applications. Feel free to add links in the comments.
Special mention must go to my friend Malcolm who provided a lot of inspiration to try recording on Linux. It was a session he ran at his studio for members of the local LUG that made me realise what was possible.