Any good Windows XP software for drawing or illustration using a Wacom tablet for example?
If your goal is to draw more like you would draw on paper, or paint, then you could be interested in ArtRage.
This program's purpose is to imitate the feeling and appearance of an actual drawing or painting. I have tested it, it feels really quite naturaly with a tablet.
I haven't used it with a tablet, but I find Inkscape to be pretty handy for vector illustrations.
Depending on your budget, here are some ideas:
Limited budget: There are a few web-based apps you may want to consider; one that I like is called Sumo Paint; there are others out there; wikipedia has a nice listing. Sumo paint is at http://www.sumopaint.com
ArtRage: They are on version 3 now, but there is still a free version which is totally worth the download. I use it and love it's ease and simplicity; I did end up buying the full version back when that only cost $20. You can do a lot with the free version and there is a lot of support from the forum of users, posting tools & add ins for the program. (I believe the same folks helped develop the a program now known as "Painter")
Corel Painter: You'll pay a lot; it's a little tricky to learn at first but only because there are SO many options; it's like having every art material under the sun! Very exciting to some of us deranged artist/technology types. I have version 9.5; they are up to 11 now.
And if money is no object, the industry standard Adobe Creative Suite would round out the Holy Grail of dream artist software. I have CS3 and I couldn't imagine living without it; they are up to CS4 now; and holy cow it's expensive. For the serious, rich, or lucky only!
I would start with the web-based Sumo or the free Art Rage; then try free demos of Painter and Adobe CS4 before splurging; each has functionality which may cater to your personal taste or methods. I hope that helps! Happy sketching!
We are developing Black Ink, a new drawing software, actually in open beta.
If you have a good graphic card, you can try it here
Black Ink is not an ordinary painting program on many aspects: its user interface, its performance on very big documents (10Kx10K) or its unique new brushes. But today it also can be called a generative art software thanks to the new controllers system.
Controllers are a whole new way to customize your brushes. You can assign behaviors in any parameter you want and make your brush act exactly as you like using a simple visual block-based system.
We need as much feedback as possible to improve it. With you it will be certainly one of the best drawing software for Windows. ˁᴖᴥᴖˀ
Note: here you have tutorials if you want
If you want your digital canvas work more like reallife(tm) ones, I would suggest out trying Corel Paint 11. I used it and if I had any more skill, it would be my #1 choice for tablet painting.