There are several threads here on Photo.SE that discuss astrophotography. They might also be of help to you, and you can find the top two here:
You might also like the Astrophotography tag.
Regarding equipment, there are some basic rules that can help you out. The first one has to do with focal length. The longer the focal length, the quicker you tend to get star trails. A 180mm lens will get star trails pretty quick, less than 20-25 seconds usually, since it is imaging a smaller area of the sky. A wider lens such as a 50mm will get star trails slower, around 30 seconds or so. A very wide lens, like 24mm or wider, will allow you to take exposures up to 45 seconds or so without visible star trailing.
Effective focal length is dependent on sensor size. If you have a full-frame sensor, a 50mm lens or wider is great to get milky way shots with decently long exposures without star trailing. On a APS-C sensor, like most entry-level and mid-level (and some high end) DSLR's, a 35mm or wider lens would be ideal for full-sky milky way imaging.
The maximum aperture of a lens can be critical to getting a good shot without star trails. I myself am somewhat limited with an f/2.8 16-35mm lens. I would recommend at around one stop faster than f/2.8, which would be f/2 or f/1.8, to get a decent night sky/milky way shot. Obviously, wider lenses give you more capability. The next lens on my list is either the Canon EF 50mm f/1.4 ($350), or the Canon EF 50mm f/1.2 ($1450). If you want to experiment on the cheap, the Canon EF 50mm f/1.8 is one of the cheapest lenses you can buy at $99.
ISO speed is a key factor in milky way astrphotography. Most milky way shots are "short-exposure" astrophotography, where the shutter is open between 20 seconds and perhaps a minute. Any longer, and the motion of the sky will start to "drag" the stars across the sensor, creating trails (startrails.) With short-exposure astrophotography, you want to absorb as much light as you can without massively blowing out the point lights of the stars themselves. Higher ISO settings, such as ISO 800 through ISO 3200, are best for short-exposure milky way shots. Higher ISO helps you keep your exposure times below the visible startrailing limit, and helps gather more light in the darkest parts of the frame. Images can be corrected during post-processing to reduce exposure back to realistic levels and mitigate noise.
If you wish to get the best sky photos, a tracking mount is a must. Tracking mounts are fairly pricey, ranging from $900 up to several thousand. There are two types, alt-azimuth and equatorial. Alt-az mounts are ok for "shorter long-exposure astrophotography", but they introduce an increasing tracking error the longer you track with them. To maintain ideal tracking, an equatorial tracking mount would be necessary. With a tracking mount, you can expose for considerably longer periods of time at lower ISO settings, gathering more detail and gaining better saturation than is possible with short-exposure astrophotography. You also have the option of exposing multiple exposures of the same part of the sky for several minutes at a time, with dark frames in between normal frames. (Dark frames are exposed for the same time as the previous frame, but with the shutter closed to gather information about fixed position and fixed pattern noise that can be eliminated during post processing.) Specialized astrophotography "stacking" tools can be used during post-processing to merge your series of exposures together and get a nicely saturated, low-noise image of the night sky. Long-exposure astrophotography also greatly expands the range of lenses you can use, anything from very wide angles, to telephoto angles, and even to mounting your camera body on a telescope for true deep-sky astrophotography.