Byte-code is most popular through its use in the JVM, but it is in no sense exclusive to the Java model. Byte-code has been used in Smalltalk since 1972, and also in Pascal, LISP (e.g. elisp can be compiled to byte-code) and ML, among many others. There is no argument, however, that Java brought byte-code into the spotlight, away from the bizarre languages favoured by academics (note: I am an academic).
Many "interpreted" languages actually translate their input to byte-code to interpret. For example, Perl internally compiles your scripts to a form of byte-code, which is being re-worked for Perl 6 to form the byte-code of the Parrot virtual machine. There has been talk of using Parrot as a target for Python, an idea no doubt related to the April Fool's joke proposing "Parrot" as a merger of Perl and Python, but this is not the initial intent.
.NET is of course a recent development in this area, and a large one at that. Code compiled for the .NET platform uses a byte-code referred to as MSIL, CIL, or merely IL, which is interpreted by the Common Language Runtime, or CLR.