Originally Posted by daffy4u
All you need is a computer with internet access wherever you are in the world. You'd surf over to the online version of the Kindle store. Buy your book, then go to your Media Library downloads section. download the book (or subscriptiion) to the computer. connect the Kindle to the computer and drag and drop the files onto the Kindle in the "documents" folder.
The only other caveat
that's perhaps worth adding is that you must have a credit card with a US billing address in order to buy books from the Amazon eBook book store.
I would, however, question the choice of a Kindle for someone who states that reading PDFs is an important requirement, given that the Kindle cannot read this format natively. The conversion software tends not to do a very good job with PDFs with complex layout - tables, graphs, etc. A machine which has native PDF support such as the Sony Reader or CyBook Gen3 would perhaps be a better choice.