If you want to photograph comet Siding Spring yourself, you won't need an expensive telescope. It's possible to achieve stunning results with just a regular Digital SLR camera and an easy to build star tracker. A comprehensive guide can be found here.
The best views of Siding Spring will be from Mars itself, however Siding Spring will also be visible from Earth as it makes its close encounter. The comet should continue to brighten in the coming months, potentially becoming a naked-eye object in late September. On Sunday, October 19th it will be possible to see the comet next to Mars as glides perilously close to the red planet.
NASA release Hubble Space Telescope image of Siding Spring. The image shows a bright dust cloud or coma surrounding the comet's icy nucleus. At around 12,000 miles in diameter, the coma is roughly the same size as Earth! The processed image (right) also shows what look to be two main jets of material erupting from the comet as it continues to approach the inner solar system.