Welcome!
Let's see, I can help with some of these. Shields can be cursed, yes. I'll never forget, my bro found a magical spiked shield! When he equipped it, however, it was cursed. DOH!
As for joining guilds, it can't actually be done in The City, sorry (not Atari 8-bit anyway). That was to be implemented in later releases of the game.
As for hacking, there some sites (notably www.gamefaqs.com) that have such information. The links at the start of this thread are a wealth of knowledge on all areas AR, not to mention the threads themselves! Read up, it's good for you.