I'm guessing you have this:
http://lowendmac.com/imacs/rev-a-imac-g3-233-mhz.html
(recommend you read that article)
This is a great computer to see if you would enjoy the mac experience. However, it's ten years old. I don't know what you mean by "all those new programs", but I wouldn't expect a gaming machine. It'd be a great internet terminal, along with the other basic Apple apps. Probably not enough hard drive space for iTunes and iMovie.
I'm assuming you want to upgrade to OS X. It probably has OS 9 on it, which is nice, but probably not what you had in mind. You can run up to OS X 10.3 (Panther) on that mac, which you can buy online from people like
OWC. Before you install that, you'll need to install some firmware updates:
http://docs.info.apple.com/article.html?artnum=86117
You can get a mac-compatible cd burner to attach, or look for an internal one. I don't think that the internal version is being made anymore, but you may be able to get one secondhand.
10.3 is two versions behind the latest, 10.5, so you can't run everything, but it's still pretty compatible. Think Windows 2000. You won't be able to install 10.4 or 10.5 on that machine.
If you want a machine that can do more, and run the latest OS, etc, a budget option would be the G4 towers. You can get these on eBay or Craigslist for under $100. You'll need 867mhz + to run Leopard. If you have a PC, you can buy a KVM and hook the tower right up. G5 towers are even faster, at a higher price. If you really want to switch, you can get a new, intel mac (which runs vista), or a refurbished intel mac if you want to save 20-30% (avalible at the online Apple Store).