This form is called in many names: the base form, the dictionary form, the imperfect form (which is a rather inaccurate term), and the non-past form. Its Japanese name (which you'll commonly find used on Japanese.SE.com) is [終止形]{しゅうしけい}, but that term refers to the shape of this form (i.e. how it conjugates) and not to its meaning.
The broadest (and probably only sufficient) definition of this form, is that it is unmarked for time and completion of the action. In essence, it's the most generic form, that tells us very little - if you want more information, you'd have to use other forms or glean it by looking at adverbs and judging from the context.
The base form does have some common uses:
Generic present: This is not truly "present" in the meaning that the event is ongoing now (for that meaning you'd have to use the present progressive tense: ～ている), but it rather refers to things that happen in general. This is very similar to the English present simple: When you say "I read books" you're definitely not saying that you're engaged right now in the reading of multiple books (at once?). You're just saying that's something that happens in general: it happened in the past, and it will probably happen again in the future. Please note, though, that there are many specific differences between the English simple tense and this: for instance, in English you generally say "I live in New York", but in Japanese you'd say:
東京に住んでいる.
Unmarked relative present: It's also very common to skip using the longer present progressive tense when it appears in relative clauses and use the base form directly. That's why the base form 住む (which is very rare in the main sentence), is mostly found in relative clauses.
In some narrative styles, especially prose, the base form can be used to indicate a vivid experience, even if it happened in the past. This is very much like the "so-and-so" present in English in colloquial narratives like "So I open the door and then he comes in and starts yelling at me [...]". The only difference is that these narratives are considered unsophisticated or even "incorrect grammar" in English (and in many other Western languages that have them), while in Japanese this is perfectly excellent prose, and you'll find in it in practically any novel, pulp or masterpiece. Strangely enough, some of the Japanese people I've asked never noticed that this is actually the so-called "present tense" used in novels, and this very important function is also neglected in most textbooks.
Future events: Generally, Japanese doesn't grammatically distinguish events that have not yet taken place (i.e. future events) from events that have already been started. It only distinguishes events that are ongoing right now (the present progressive tense) and events that are already completed (the various past and perfect tenses, especially the た tense), but it doesn't distinguish future events (as long as they are quite certain) from events that happen in general or are otherwise unmarked for time.
The only way to distinguish the future from the general present in Japanese is to look at contextual cues and adverbs that point to time. Contextual cues are easy - if you think the speaker is talking about the future based on what he previously said, then he probably is, case closed. Time adverbs are also very easy in some cases: if you hear the adverb 明日 ("tomorrow") then the sentence is about tomorrow, case closed. You should also pay attention to other adverbs such as また or かならず, that most of the times firmly set the sentence in the future.
Completely out of context, 映画を見る just means "seeing a film". Yeah, it doesn't have any time at all, like the English gerund in this case. Add context or more adverbs and complements to the sentence, and things get clearer:
- その映画は明日見るよ。I'll see that film tomorrow.
- 映画を見るのは楽しいですね。Seeing films is fun, isn't it?
- 毎週、映画館に行って映画を見る。Every week, I go to the cinema and see a film.
