I’ve been really groovin’ on the Open Office apps of late, the final nail in the coffin of Microsoft on my desktops (excluding XP on one machine). Wanting to go deeper with the OO suite, I went in search of books or other resources, and discovered there are some great PDF manuals on OO’s Documentation site. You can also get a number of them in dead tree editions, such as the third edition of the OO Writer Guide, a 450 pg tome, via Lulu, for US$20.
The Documentation site has some really good How-To pieces, lots of templates, articles about OO, FAQs and other useful stuff. Worth spending some time poking around there, especially if you’re new to OO.