someone desperately need a captcha tool on their blog...

Not sure about the performance implications of FindControl.. But this one is pretty close to what you originally wrote

for (int i=1;i<4;i++)
(Controls.FindControl("labela" + i.ToString()) as Label).Text = "something";

Maybe Adobe: Apps for iPhone[^] is what they are trying to combat?

I really do admire the people putting countless hours every day / week into a project that benefits a community. I do have very little experience and grasp of the various open source licenses and "free" software and the open source business model, but if i were this guy i'd be looking into other ways of generating income based on my work. Income mechanisms that didnt make my userbase feel uncomfortable about using my work. One thing i'd look into is a paid extended support license, the software is free, there is a limited support, but if you want premium support on it, pay. Another would be to put alot of my time into doing contract work for others, by using that software, and letting it mature with the usage. This way i'd also get more direct experience on the way the software is used, and in what areas the software would need to be improved.