Aria2 is a fast download utility that you use in the Command Prompt or xterm. To compile aria2 for Linux, install the following packages. More here
Although Debian 5.0 Lenny has libc-ares2, Debian 4.0 Etch and Debian 3.1 Sarge don’t have it. As a user of Debian Sarge, I had to compile c-ares myself to enable asynchronous DNS resolution in Aria2c. I downloaded c-ares source from c-ares.haxx.se and compiled it statically.