easy, find a cool name + announce it here + get beta testers
it's told to join the GDF is a good idea, well your decision.
communication with other developers is helpfull.

You make it sound so easy Anyway, I was asking how I can be listed on Gnutella.com or Gnutelliums.com, as an official client? Didn't find a single e-mail address there!

Don't you need a license or anything?

Who pays, and maintains the Gnutella servers? And how do they recover the amount spent?

Cookies are handy in advertising. However, they do not extract any personal identifiable information, but only info. (Like, which ads have been shown, for how long etc.) to enhance the user experience.

My Question is: Are Cookies considered as Spyware?

I am not writing anything. Might write in the future. Give me your the concerned email address concerned, anyway, for reference

Write the program first, then come back and let some people know it works, see what people think before you make a big deal out of it. There are many, many programs and some are now un supported because people found out they can't make a zillion writing a client and gave up.
If you are here to make a buck, go write a PDA ap or something, gnutella is not the place for greed.

Or make a kickass gnutella app that blows the others out of the water. I don't think anyone here would mind seeing that

OK OK! Cool down! I am not writing anything! I was just giving an example

Do you think it's easy to write an application? Do you think you might use the application for free, while the developer (who has toiled for hours) get's nothing? What if small mini-sized ads are featured, only such that the developer could afford hosting, and development of the application. Would you be happy with the person who deserves all the credit, gets something at-least? how would you answer this question

Programmers should get something for their work, of course.
Maybe it's fun, money, fame, experience what they get...

...the author could choose IMHO. Open source is fine for many reasons, but I also accept ads or paying a small amount for an ad-free version. If a program is worth to be used, it's worth to give something back to the programmer!