If you run Sid (the Debian unstable release), you can install Regina from the usual Debian servers like any other package:
example$ apt-get install regina-normal
Sid always ships with the latest version of Regina (though it may take a day or two for new versions to appear on your Debian mirror).
If you are a C++ programmer and you wish to build Regina into your own projects, you will also want the package regina-normal-dev.