Your interpretation is quite good.

In Japanese, the -te iru form indicates something that is directly observable because it has actually occurred. Somewhere between “to have been –ing” and “to be –ing” in English. How you translate it depends on the context.

It indicates a past continuous action that has continued up until the present moment.

The non-past form is more abstract, and can refer to things that are happening now (as general trends rather than specific instances), but also things that have not happened yet. Somewhere between “to be –ing” and “will –” Again, how you translate it depends on the context.

I posted about this on the forum a while back. Take a read here:
http://www.japanesepod101.com/forum/viewtopic.php?t=430&highlight=saq

But considering a different example, perhaps it is more clear to me
“Every morning I wake up at 4:00am”
“Every morning I have been waking up at 4:00am”
The former means that in the past, present, and future, I wake up at 4:00am. The latter indicates that I have been waking up at 4:00am for some unusual reason (perhaps the baby crying). But this action may or may NOT continue.

まい　あさ　午前４：００ 起きます。
まい　あさ　午前 ４：００起きています。
Hopefully this is correct. Does 起きています mean that I have been doing this but may or may not in the future.
Thanks
ジョン

Well, I don’t have much time must return to the books, this friday I have a japanese oral test, wish me luck!

It can be difficult for learners to pick up on how language is used because we don’t hear it often enough. And reading materials are often textbooks rather than more everyday materials.

“Maiasa suru” = “to do something every day”
“Maiasa shite iru” = “to have been doing something every day”

Different nuances because of different aspects, but both are acceptable.

#2 As Jason said, “kite iru” does not mean “coming”. It’s not an irregular case. It makes perfect sense if you think about it; “kite iru” is NOT a verb in continuous form.

1. The “iru” is being in its original sense of “something existing in a particular location”.
2. Remember that the -te form of a verb implies that “first you do this, then you do this.”

Put these two things together and you see that in the phrase “kite iru”, first you “kite” (come), and then you “iru” (be/exist in a place). That’s why it means “come somewhere and still be there now”.

However, under the same circumstances of having recently put on weight, one of my tennis mates tried to say the same thing in a slightly more humorous way using the word 「育てる」, which means to rear or raise. Was this a comparison to a pregnant woman, or is it a common way of saying this?

友達はイギリスから私に会いに来ている。
My friends came from England to see me (and they’re still here).

I wouldn’t use this with going to places in everyday life like school, the store, etc., even though you’re there for a while and you’re expected to go back. 来ている is more of a “guests in another’s home/country” kind of word.

On the other side, I’ve heard both 来ない and 来ていない to mean “they’re not here.” It’s my sense that in a phrase like, まだ来ていないなあ, there’s a feeling of “well, they’re not here yet, but I still think they’re coming.” While まだ来ないなあ is more like “they’re not here yet. Maybe they’re not coming.”

This is a most interesting topic. The other one that confuses me from time to time is the use of past and present. e.g. When waiting at a bus stop and the bus comes into sight, an English person would say that the bus is ‘is coming’ (present progressive tense) or the bus has ‘come’ (past tense). I think a Japanese person would say the bus ‘comes’ (present tense) because the action is in the present and not complete. I’m not sure whether the present progressive could be used, but I suspect not as this would imply that the bus has already come and continues to come; maybe implying that it keeps to the timetable. Any thoughts?