I am fascinated to learn about the Oort Cloud. Does anybody know if the boundary of the Oort Cloud extends to the Heliopause? Also, since our sun has an Oort Cloud, do other stars/suns also have Oort Clouds (or something similar) surrounding them as well?

Good questions.

The Oort cloud is an immense spherical cloud surrounding the planetary system and extending approximately 3 light years.

No one knows just how far away the heliopause, or "edge" of the heliosphere is, but it could be as far away as 100 AU.

Recall that AU = Astronomical Unit = earth's distance from the sun, which is about eight light-minutes.

Thus it appears that the Oort cloud extends way beyond the heliopause.

As for your question about other stars having Oort-like clouds of cometary bodies, I would guess that nobody really knows, considering that even the discovery of planets around other stars has been confirmed only in recent years. But given the myriad number of stars in the vastness of the universe, it's certainly plausible and even likely.

Very insightful answers, Professor. The links you provided have so far given me several hours of great information to read, and I look forward to referring to these sites often.

One of these sites has (surprise, surprise!) spawned more questions. http://www.windows.ucar.edu/tour/link=/glossary/solar_wind.html&edu=high on the Solar Wind
"The particles of the solar wind, and the Sun's magnetic field (IMF) are stuck together, therefore the solar wind carries the IMF (interplanetary magnetic field) with it into space. Once blown into space, the particles travel at supersonic speeds of 200-800 km/sec and do not slow down until they reach the termination shock within the heliosphere, where the solar wind slows from supersonic to subsonic speeds." Wow. This quote makes me wonder... if the solar wind is slowing down from a supersonic to a subsonic speed at the termination shock within the heliosphere, what happens to the solar wind and the Oort cloud material at that point? Does the solar wind "bounce back" unto itself, reverberating back within the Oort cloud, causing the comet material and all else within it to move about? Or rather, at that point would the solar wind just cease to exist?

The term 'subsonic', as it applies to the solar wind speed at termination shock,is misleading, in that we define that word to mean 'below the speed of sound', which in air is about 700 mph, higher in denser materials. At termination shock, the solar wind sped is reduced from about a million miles per hour to some 250,000 mph, still way above the speed of sound. The term subsonic here really implies that a shock wave is formed, similar to the shock wave and sonic boom when a jet, bullet, whip, etc., breaks the speed of sound in air. The shock wave is caused by the high temperature solar wind plasma particles wind colliding into the cooler plasma particles of the 'gallactic' wind of other stars...the interstellar winds, if you will. The solar winds then travel beyond the termination shock into the heliopause, perhaps 150 AU away from earth, where they are then absorbed by the interstellar winds (the winds from other stars), at 'subsonic' speed, and become a part of them, no longer characteristic of a solar wind since the charged particles of the interstellar winds dominate. In effect, they sort of cease to exist. All is not lost however, since the shock wave sonic booms at termination shock travel back towards earth, where they may soon be detected by NASA in upcoming missions.

My earlier response about subsonic versus supersonic definitions is confusing. While the speed of sound in air at 60 degrees F is about 700 mph, its speed dramatically increases at much higher temperatures. The solar winds are ionized particles in the plasma state with extremely high temperatures....somewhere in the range of 1/4 million degrees or so. Thus, when one refers to the subsonic or supersonic speed of sound, it must be referenced to a medium, temperature, and other variables (pressure, e.g.). For the solar wind , its speed is in reference to the speed of sound in the plasma gas..the gasdynamic speed of sound...which at those hot temperatures are in the 50,000-250,000 mph range.
To the heliopause....and beyond!..go the Voyageur spacecrafts!

Some more info on the Oort Cloud can be found here, which is part of the excellent The Nine Planets, which in turn was a link found at Phil Plait's Bad Astronomy Info (don't let the name throw you -- it's quite good).

Quoting from the first site above, which appears up-to-date: "The very existence of the Oort Cloud is only a working hypothesis. Our only evidence is very indirect."