Well this is really pretty easy. Let's see. First you need to stop off at the company that makes the CPU. You should be able to down load a PDF spec that will outline all of the instructions that your particular variant of the ARM processor can execute. Then you need to determine which assembler you are going to use. Probably something from GNU, so you need to get the manual for that. That manual will have all of the directives and formats used by the assemble to translate assembler into machine language. Next you will need to read the man pages for maemo. basically section 2 and 3. That is about it.

As to a book, all that would be in the book would be the machine instructions, addressing formats, etc.; all of which is in the spec sheet from the cpu manufacturer. Assembler directives, etc. are from your assembler vendor. OS callable routines are in the maemo man pages. The book would add little except sample programs.

The previous comment about growing a big head is right on. In assemble you must keep in your mind the contents of all registers and status flags, and know how each op code will effect them.

Me, I would follow Atilla77's suggestion of python, with a few optimized routines. I read a report a number of years ago that said it takes about 350 lines of assembler to do the same job as about 150 lines of C. Python wasn't mentioned, but I'm pretty sure that it would be well below 100.

I've done assembler programming as a job. I've been programming since 1969. My shortest assembler program was a CICS transaction that was 3 lines of code. It was used for a number of years by my employer. Avoid assembler programming!