Miking Vocals

The first step to recording vocals is picking what type of microphone you want to use but also keep in mind the tips.

Tips

• One thing to keep in mind is the Proximity Effect, as the vocalist gets closer to the microphone (under a foot) the sound will change resulting in an increase in bass frequencies. The proximity effect only applies to directional microphones.
• Pop Filters can help remove the pops on "p" and "b" sounds. Usually setting the pop filter mid way between the vocalist and the microphone is standard when using a large diaphragm condenser (apprx. 4" and 4"). A cheap trick for making your own pop filter and de esser is to tape a pencil on the front of the grill of a mic (works best on a large diaphragm condenser) by taping a pencil vertically on the font of the grill it acts as a diffuser and can help prevent pops and sybilance.
• Also keep in mind that any instruments, Snare Drums, Guitars, and Pianos that are present in the room you are recording in, will reverberate right along with the room, occasionally making substantial noise. Make sure to remove or dampen any such instruments before recording.

Condenser Microphones

Condenser microphones have low distortion and a high signal to noise ratio, and tend to produce a more "true" reproduction of the voice. Condensers are more appropriate for singers on vocals where you want to reproduce the singers voice in a clear fashion as opposed to something edgier. Most vocal microphones use a large diaphragm because it is slower and more pleasant to the ear because it smooths out transients. Keep in mind that condenser microphones need 48 volt phantom power though most mixing consoles or microphone inputs have this capability. Condenser microphones tend to be highly sensitive and can easily pickup small background noises like a squeeking of a chair, outside traffic noise, or an airvent.
Examples: U87 TLM 103 (cheaper version of the U87)

Ribbon and Tube

Ribbon and Tube microphones can reproduce an older style sound, and tend to be warmer than condensers especially when paired with tape and quality preamps.

Vocal Dynamic microphone

Dynamic microphones can handle sustained loud input volumes (screaming etc..) without alot of distortion. However, they have a higher level of distortion to begin with. These can be more forgiving in some respects, most notably on your pocketbook. For example, the SM58 sells for around $100 and is one of the most widely used dynamic vocal mics.
Dynamic microphones are less sensitive and thus less sensitive to ambient noise than condensers, less reflections will also show up on the recording. This can be particularly useful when recording loud bands at the same time as a vocalist, providing better, though by no means perfect, isolation.
For a unique effect, you can tape or hold the side of the grill on a dynamic mic like a 57 or 58, you will sometimes see vocalists do this on stage at hardcore shows. It changes the frequency response when you do this and it can produce a more bassy "gutteral" vocal.

Links

Fixing Out of Tune Vocals

Vocal Styles

Opera

Recording an Opera, or any classically trained, singer can provide a plethora of new challenges.
First of all, Opera sings have a notoriously wide dynamic range. They often go from very quiet to impressively loud in a single song, it might help to minimize some of the dynamic range (and potential for peaks) by sending it through a compressor even before sending it to tape (or your DAW) (note: you can't undo compression so make sure you have a setting you are sure to be happy with).
Also, depending on the skill of the singer, they may be able to "play the acoustics" of the room. That is to say, even when singing quietly, a skilled opera singer can make the room itself reverberate in a pleasing way.
Taking these things into account, it is probably best to use a condenser microphone to record opera. However, be sure to place the singer a good distance from the microphone, experimenting with anywhere from 6 inches to a foot away should be fruitful. Also, consider using a room microphone setup along side the primary microphone to capture the sound of the room. This should allow you to capture the full depth of the performance.