Gifts generally reflect the facet represented by the spirit that granted it. A spirit associated with learning might be able to teach a garou to read any language. A spirit associated with war might be able to teach a garou to strike so hard she can cut through armor like butter.
Gifts taught by spirits are learned virtually instantaneously. The spirit simply grants the ability to the garou and gives it some instruction in how this new power works. Spirits generally will ask for chiminage for teaching a gift. The greater the gift, the greater the chiminage. A minor gift may require simple chiminage like planting a tree or killing a minor Bane. A truly powerful gift may require the garou to swear to cleanse an entire toxic waste dump or swearing that he will never set foot in a city again.
Sometimes garou can teach gifts to other garou, but this process generally takes several weeks (or months!) and is fraught with danger as the student practices with his new power. Some kinfolk can learn gifts, but these are exceptionally rare individuals. Most kinfolk know no gifts. Even the most adept kinfolk probably only knows one or two.
Mechanically, gifts range in level from one to six. Garou cannot learn a gift that's level is greater than the garou's current rank. Garou have access to them based based on their breed, auspice, and tribe. While they can learn gifts not of their breed, auspice, or tribe, it is more expensive to buy these with experience points. Storywise, spirits are less likely to teach those gifts to garou from the wrong group and will demand heavier chiminage.