Modern pickups are tailored to the sound desired. A commonly applied approximation used in selection of a pickup is that less wire (lower electrical impedance) gives brighter sound, more wire gives a "fat" tone. Other options include specialized switching that produces coil-splitting, in/out of phase and other effects. Guitar circuits are either active, needing a battery to power their circuit, or, as in most cases, equipped with a passive circuit.
As you start practicing, your fingers may be sore for a while, but that will pass with four to six weeks. One thing I want to warn you about is that new guitar players can get frustrated when they can’t play clean chords because they try to switch between chords too soon. Often, they try to switch chords before they’ve really learned and memorized each chord shape. For now, don’t worry about switching chords and just work on each shape, getting them down, and going right to them.

All three principal types of resonator guitars were invented by the Slovak-American John Dopyera (1893–1988) for the National and Dobro (Dopyera Brothers) companies. Similar to the flat top guitar in appearance, but with a body that may be made of brass, nickel-silver, or steel as well as wood, the sound of the resonator guitar is produced by one or more aluminum resonator cones mounted in the middle of the top. The physical principle of the guitar is therefore similar to the loudspeaker.

A guitar strap is a strip of material with an attachment mechanism on each end, made to hold a guitar via the shoulders at an adjustable length. Guitars have varying accommodations for attaching a strap. The most common are strap buttons, also called strap pins, which are flanged steel posts anchored to the guitar with screws. Two strap buttons come pre-attached to virtually all electric guitars, and many steel-string acoustic guitars. Strap buttons are sometimes replaced with "strap locks", which connect the guitar to the strap more securely.
UPDATE: SEPTEMBER 3rd, 2010 -- Good evening, and hi everybody! I get requests to add tabs once in a while, and for years one of the most common requests has been 'Psychic Hearts', and more recently 'Trees Outside the Academy'. I resisted for years, but boredom and the need to please has a funny way of making things happen, so I'm proud to bring you tabs for the entirety of "Psychic Hearts" and its related tracks, as well as the majority of "Trees Outside the Academy". I was originally planning on providing bass tabs as well as the Mascis solos, but I decided I wasn't that desperate for accolade. With all this attention on Thurston, I felt bad for Lee, so I've updated my outdated tab for his excellent solo acoustic piece "Here" (located under "Other Tabs") with the proper tuning, which also happens to be the tuning for the equally excellent "Lee #2", so I've updated that one too!
Electric guitars can have solid, semi-hollow, or hollow bodies; solid bodies produce little sound without amplification. Electromagnetic pickups convert the vibration of the steel strings into signals, which are fed to an amplifier through a patch cable or radio transmitter. The sound is frequently modified by other electronic devices (effects units) or the natural distortion of valves (vacuum tubes) or the pre-amp in the amplifier. There are two main types of magnetic pickups, single- and double-coil (or humbucker), each of which can be passive or active. The electric guitar is used extensively in jazz, blues, R & B, and rock and roll. The first successful magnetic pickup for a guitar was invented by George Beauchamp, and incorporated into the 1931 Ro-Pat-In (later Rickenbacker) "Frying Pan" lap steel; other manufacturers, notably Gibson, soon began to install pickups in archtop models. After World War II the completely solid-body electric was popularized by Gibson in collaboration with Les Paul, and independently by Leo Fender of Fender Music. The lower fretboard action (the height of the strings from the fingerboard), lighter (thinner) strings, and its electrical amplification lend the electric guitar to techniques less frequently used on acoustic guitars. These include tapping, extensive use of legato through pull-offs and hammer-ons (also known as slurs), pinch harmonics, volume swells, and use of a tremolo arm or effects pedals.
Guitars have been played since the Renaissance era, after descending from the ancient Greek instrument, the kithara. Or, at least, that's how the theory goes: the only real proof for this is the similarities between the Greek word and the Spanish word, quitarra. Early guitars often had four strings, evolving into the six-string version we know today in the late 1600s. Anton Stradivari, the famous violin-maker, also had a hand in making guitars. There's now only one Stradivarius guitar left in existence.