wololo.net/talk

the entry point, or whatever you want to call it. I used to think it was 0x08800000. *FailFish*

it seems to be 08804000 for the game I'm using. But it also say there's a segment 0 and segment 1

segment 1 doesn't contain any code so what is it then, the heap?

Relocatable game eboots are allocated to 0x08804000. some games are also statically compiled to that address, I'm not sure if other static addresses are used officially.
The segments could be data other than code, it could be heap, text, or data, it depends on the game.