Yesasia, Paletweb and Eurotaku all stock foreign PC games. Most of Yesasia's are in Traditional Chinese which may put you off, but on the other hand they're generally half the price (or even less) of the Japanese version, and they usually come with good extras (OSTs, artbooks, guidebooks, etc) too. Other than that you options are: proxies, lucky forum sales or trips to Japan.
This really depends. I personally think the Falcom website is the best place for ordering Falcom games. Just wait for the today special and pick up all the games in 1 go. The only downfall is the expensive shipping from ordering the Falcom site.
Play-asia is a good choice for ordering the games in other langauge form, like the chinese version of Falcom games go for a much lower price then its Japanese counter part.
If you looking for it used, i suggest looking at yahoo auction, get a deputy service of some sort and bid on it. I think i bought Ys 6 limited edition for 2000 yen on yahoo auctions. After all the fees, i think i paid about 45$ US total.
Those are my most recommended place on getting falcom games.