Sergio,
Thanks for the compliment. I enjoy photography as well as our beautifully engineered and executed pistols.
While I'm using a good camera and lens for these photos (I have a Nikon D2X and use a 85mm Nikor Micro lens) you can get very good results with a very low budget.
Start with a purpose built digital camera rather than a cellphone camera.
The key to this is controlling light and keeping the camera steady.
The light needs to be soft diffused light. The free version of this is outdoors in shaded sunlight. Flat even soft lighting tends to bring out the finish of a firearm without creating lots of reflections.
I use flat diffused florescent lights indoors. You can use inexpensive clip on lights with reflectors and something over them (like a white sheet) to diffuse the light.
A tripod that can steady the camera while you compose the picture is essential. If you use the self timer to take the photo, it will eliminate the camera shake of pressing a shutter button.
To get sharp focus, use an aperture priority setting if your camera has one. Set the aperture for a high "F" stop like F16 or F32 and a long exposure time. Auto-focus cameras can be hit or miss, especially when taking closeup pictures. A SLR helps, but is not necessary if you're patient.
I built a little stand out of plastic CPVC pipe that supports a background cardboard sheet. If you build it so that the cardboard curves down behind the object, it will blend. I use gray or black for many photos, but white and other colors can be used.
Here's a plan for a photo light box:
http://www.pbase.com/wlhuber/light_box_light_tent
This is the one I used.
The light exposure of the camera may need to be overridden (generally - F Stops). This is because the meters are calibrated to average 18% light reflectance as the proper exposure. Our firearms are either darker than that (if blued) or brighter (if stainless steel). If you slightly under expose, you can make corrections later in a computer image editing program like GIMP or PhotoShop.
Marc