If you look at the table in the article, it says the iBook G5 will start
shipping second quarter to Apple, so (as much as I hate to say this since I was hoping to get an iBook G5 before I start college next fall) it likely won't be ready for WWDC or Macworld Paris. However, the table says that the delivery date for the PowerBook G5 will be in "2Q 2005" meaning, we can expect it for WWDC, at the latest.
The iBook G5 looks like it won't come out until after Macworld Paris (and the Back-to-School season), possibly as a quiet release right before Christmas 2005 or Macworld SF 2006 (probably not though), at the latest.
Here is my guess for release calendar*, up to January 2006:
March/April - releases for the educational buying season:
-- eMac G5 - 1.6 GHz on both models, w/ the high-end having similar specs to the low end iMac G5. Improved graphics for future Tiger Core Image support. Now with iWorks and iLife '05.
-- iBook G4 update (in keeping with the upgrade cycles) - 1.33/1.5GHz w/ improved graphics for future Tiger Core Image support. Hard drives go to 40GB and 80GB. Now with iWorks and iLife '05.
May - a quiet overdue upgrade, and tons of speculation...
-- iMac G5 update - 1.8/2.0GHz; otherwise, just speculation about WWDC (if you want some more of updates here, an iPod and iPod mini updates would be nice, w/ 20, 40 and a new 60 GB and a 5 GB model, respectively...15 hours of battery life for iPods, 10 hours for iPod mini, and price drops for across the board

)
June - releases for power users, just in time for WWDC
-- Tiger, ready to roar

(Hopefully with Java 2 Platform 5.0, also called Tiger, I believe.

)
-- PowerBook G5 - 1.6GHz/1.8GHz with 512 RAM base on all models and Tiger. New 13" PowerBook (no more 12"). 128MB Graphics on all models, among other nice new upgrades.
-- PowerMac G5 update - Dual 2.0, 2.5, and 3.0GHz, price drops (hopefully), and some other nice upgrades.
-- lots of high-end HD stuff
July - all about the budget consumer...
-- iHome (possible, still waiting to see some more solid evidence on this rumor); will have support for HDTV w/ Tivo; built-in Airport Extreme so you can connect to your network, and control your TV from your 'Book or 'Mac at home and even possibly load stuff up from your 'Book or 'Mac on screen with a remote control.
-- Updates to software, and accessories for all.
-- Possibly speed bump upgrades, maybe a Mac mini upgrade to 1.5/1.67 GHz
-- Only major update could be iBook G5 (more likely will be an iBook mini, starting at $799), though its doubtful since they will want to "milk" (I couldn't think of a nicer term

) with the PBG5 and the Back-to-School deals with the iBook G4/iPod combo (or iBook mini/iPod combo).
-- more HD stuff, aimed at the budget consumer.
August/September - getting ready for school again...
-- Back-to-School deals, with iBook/iPod combos leading the way.
October/November - finally, in a quiet release...(and coincidentally, just in time for the holiday season...)
-- iBook G5, w/ 1.5 and 1.6GHz models, 512 RAM base (finally!), same graphics probably if they upgraded them in March/April (according to this calendar) and other nice stuff starting at $1099.
-- iHome update (or release if they haven't released it yet, assuming the pictures are true.)
December - the holidays are a time of giving...for Apple employees, Christmas bonuses!
-- 500% Profit increases on all lines, compared to Christmas 2004, with the iHome and iBook G5 leading the way! Apple hits 1 Billion in profits for this quarter alone! (ok a little exagaration but its will be a really good christmas season for Apple

).
January 2006 - a new year, a ton of new Apple products and upgrades
-- Macworld - Jobs keynotes again, with a Mac mini to 1.5/1.67 G4s if it hasn't happened already, and announcement of plans for 2006; updates to iWorks and iLife...maybe something new for both products i.e. spreadsheet for iWorks and something revolutionary for iLife? We'll find out in 12 months

...
* - calendar is based on information/speculation from comments and rumors in websites, forums, and blogs, mainly apple.com, macworld.com, macrumors.com (Buyer's Guide help in speculation), and thinksecret.com, over the past 6 months, as well as, Apple's history about releases, new products, etc.