This is not for the faint of heart. Use a clean lenspen (I've done this before, do this at your own risk), set the camera to sensor cleaning mode, the mirror will flip up. Carefully, use the sponge edge of the lenspen and wipe it from left to right in one smooth movement without putting too much pressure. Only go one direction until complete coverage of whole sensor. Test at small aperture again to check if dust is still there. A disclaimer: do this at your own risk.

Use [img] and a close img tag [\img ] at the start of the image HTML file ---> http://Flickr.commy/lalalaphoto.jpg

Buy from eBay, it's only about rm5 plus shipping

What is your priority? portrait/still life/indoors or "landscape"? Notice the "" on the landscape? That's because using a fisheye for landscapes will only get you a WOW factor for a couple of shots. After that, it'll become dull and cliche. For landscapes, you're better off getting an ultra wide angle ie. Canon 10-22mm, Tokina 11-16mm f/2.8, Tamron 10-24mm, Sigma 10-20 just to name a few.

I'd suggest you get a flash first. Preferably Canon's own flash.

A flash will help out a lot for indoor shots, portraits (filling in shadows, eliminate red eye etc.), macro...

As for either Sigma or Tamron, I'd suggest the new Sigma 10-20mm F3.5 EX DC HSM. Constant aperture, HSM (not so important for landscape photos anyway, but what the heck), new coatings.

But if there's extra cash, I'd recommend the Tokina 11-16mm f/2.8. Shorter range, but the constant f/2.8 is some what more useful.