Walls and Ceilings - is this wall load bearing?

I know this can be a complicated question. What is the easiest way to determine if a wall is load bearing? The wall is on the first floor of a 2 story that has a full basement. The joists in the basement (directly under the wall in question) run parallel to the wall, however the joist under the wall in question is doubled (2 2x6's). The joists in the second floor ceiling (one floor ABOVE the wall) are also parallel. I can't see the joists directly above the wall due to ceiling/floor covering. The wall that is at a 90 degree angle to the wall in question sits over a beam in the basement ceiling that is supported by columns to a footing so it seems that it is definitely load bearing. Could both walls be load bearing? Do I need to make a hole to see the joists directly above the wall? If they are also parallel to the wall does that make the wall non-load bearing? Hope I didn't make this too confusing.

They could both be load bearing walls, a tad bit hard to visualize. Any chance ya could post a couple of pictures somewheres on the web where I can take a better look see?

Determining if a wall is load bearing can be difficult for an experienced builder. Even building inspectors rely on the "when in doubt" principle... when in doubt, assume the wall is load bearing and act accordingly.

Renovations can cause weight to be transferred onto formerly non-load bearing partition walls.

Generally, load bearing walls are perpendicular to the joists they support. If two separate floor joists or ceiling joists intersect over a wall, that wall should be considered load bearing.
You should consider all outside walls load bearing. If the house has been remodeled, a former outside wall could now be an inside wall.

In multi-floor dwellings, posts and beams in the basement indicate bearing walls above them, even up two floors. Multi-floor bearing walls may not be directly above each other.
In large homes with complex floor plans, the basement can be a maze of carrying beams and posts. Careful inspection is necessary to determine how beams support the house.

If you have any doubts, call your local building inspector to take a look and make recommendations. You will need to talk with him any way regarding permits and inspections.

The reply you got over at the Breaktime forum of Fine Homebuilding covers just about everything (including why so few are willing to answer this type of post).

I actually posted the same question on three different forums (I hope that isn't poor form) I figure,the more info the better. As my "handle" implies, I'm an amateur and I have no intention of laying into any walls without doing a lot of homework, including an onsite inspection, I'd just like to get an idea of what I'm getting into before I start. I didn't know what questions people would or wouldn't answer I just thought I'd ask. I've actually received a lot of very helpful replies. Thanks all.:)

That's what these forums are all about. I have no problem sending folks to particular forums that are the best, IMHO, for particular topics.