A good rule of thumb is to remember that have got can be used to mean have1.
1(Though it's very likely that haven't got any money in the example should mean "doesn't have any money", the alternate interpretation in BrE, "haven't obtained/received any money", can't be ruled out. For more details, see the discussion in comments under this answer.)
One interesting point made in The Cambridge Grammar of the English Language (CGEL) on page 112 (which is along the same lines as given in other answers here) is that,
In both varieties [of have got, in BrE and AmE], however, the perfect origin of have got is reflected in the fact that the have component of it is an auxiliary, absolutely incompatible with do (*We don't have got enough tea).
(Note that an asterisk (*) denotes ungrammatical usage.)
Besides mentioning that have got is informal and characteristically BrE, CGEL also mentions that it's usually used in the present tense. From the same page:
Have got is restricted to informal style, but is otherwise very common, especially in BrE. The have or have got has no past participle form (*She had had got a Ph.D.): in this respect it is like the ordinary perfect auxiliary. Unlike the perfect have, however, the idiomatic have also has no gerund-participle: %She almost regrets having got a Ph.D. has only the non-idiomatic meaning "having obtained", and hence requires gotten in AmE. The plain form is very marginal: ?She may have got plenty of money but that doesn't mean she can push us around. The preterite [i.e., the past form] is certainly possible (She had got too much work to do), but it is fairly uncommon: have got occurs predominantly in the present tense.
(% indicates the grammatical status is grammatical in some dialect(s) only, and ? of questionable grammaticality.)
So, here is my take-home message:
(Note that all have gots below refer to have got when it's used to mean "have".)
- have got can mean have (but remember that you can't always use have got for have),
- have in have got is an auxiliary verb (so She said she hadn't got any money is fine);
- it's fairly uncommon to use have got in the past tense (so the advice "the form of 'to have got' in the past simple tense is 'had' NOT 'had got'" is sound, even though you can use had as well),
- but above all, remember that have got is informal, and
- it's always safe to write have when you mean have got. ;-)