Hudson hasn’t got around to creating a Bomberman game for the PlayStation Network, but as a quick replacement the PsOne remake of the Bomberman game for the NES is now on the Japanese store. Like all of the PlayStation archives it costs 600 yen ($5). However, if you play the downloaded game on the PSP you won’t be able to use the multiplayer features.
Also on the store is a game in the Lord Monarch series, which was developed by Nihon Falcom. I wasn’t aware any installment came out on the PsOne, but Lord Monarch: New Gaia Kingdom Chronicles is up there. Kokobure Pukka is one of the more obscure titles on the service and it’s a digging game.