Compiler construction in c

An easy way to create a compiler is to use bison and flex (or similar), build a tree (AST) and generate code in C.
With generating C code being the most important step.
By generating C code, your language will automatically work on all platforms that have a C compiler.

Nicklaus Wirth's Compiler Construction is a very good textbook on the basics of simple compiler construction.
He focuses on top-down recursive descent, which, let's face it, is a LOT easier than lex/yacc or flex/bison.
The original PASCAL compiler that his group wrote was done this way.
Other people have mentioned the various Dragon books.