To download the latest release version of Hatari, have a look at the Hatari download area.
Note that many Linux distributions already ship an RPM or DEB packaged version of Hatari. You might want to have a look at those first, but often they are not as up to date as the official version here.
If you have installed Mercurial, you can also grab the latest development snapshot of Hatari. You can clone the repository like this:
hg clone http://hg.tuxfamily.org/mercurialroot/hatari/hatari
By visiting this URL, you can also browse the source code repository online.
For compiling and running Hatari, you must have installed the following libraries and their development versions:
Following libraries are optional, but for your full Hatari pleasure, we recommend to install them:
Hatari also needs a TOS image file for running. But since TOS is still
copyrighted, we can not put such an image file here (and please don't ask us
to mail you a TOS images, too).
However, if you have an original Atari ST, you can make an image file from its TOS ROMs. There are programs like TOSDUMP.PRG or WINX that can create TOS images on a real ST.
Note that depending on the machine type that you want to emulate, you can only use certain TOS versions. The plain ST mode only works with TOS 1.00, 1.02, 1.04, or 2.06. STE mode requires any of the TOS versions 1.xx or 2.xx. TOS 3.0x is for TT, and TOS 4.0x is for Falcon mode.
If you don't manage to get a real TOS image, you can also try the free EmuTOS, it is a TOS replacement and you can already use many programs and play some games with it. The official release of Hatari is normally shipped with the latest EmuTOS image.
For those who want to test Hataris hard disk image support: 80 MB ACSI hard disk image (compressed with gzip to 90kB).