There are some free web sources: First, E-fairies may still be available. This is a fairly large pdf from Bastion Press which previews and supplements their book, Fairies. The site might still be dragonwing press but I haven't looked there in a long time. If you don't have it and can't find it, send me a PM with an email I can forward you a copy to.
Secondly, there are also the Fey Feature archives on the WotC's website. I can't seem to post the URL correctly. They also have a homebrew section for earlier editions where creatures were posted. I used to monitor that site and Bhu still frequents there. Unfortunately, WotC made it user unfriendly (and I'd say user surly but I'm biased) so I rarely go there any more.
Many Fey creatures were updated on EnWorld's Creature Feature site. You can check the homebrew section as well to find some fun things.
Some of the fey creatures are also available in the Tome of Horrors. The Tome of Horrors revised edition (updating it to 3.5) is only available as a pdf as it was deemed to expensive to reprint. It can be had relatively cheaply on sites such as RPGNow.com. Occasionally, the publisher releases it for free so you can check for special deals.
Other online sources are the free materials from Kobold Quarterly and other gaming sites, but it will be hit-or-miss as to whether they specifically have Fey creatures.
The last free site I'm going to mention is the D&D Wiki which has been posting all the Open Game Content from as many D20 books as possible. You can find a ton of stuff there but you'll have to do a lot of poking around.
As with anything else, you'll have to recheck the statblocks. Not all material is good about following the rules (and 3.0 material isn't always updated). It's fairly easy to update to 3.5, but time consuming. Monster feats weren't based on HD until 3.5.
Debby