A quick google search makes me think it kinda-sorta partially works, e.g. route directions don't seem to load, but looking up adresses should be fine. Don't underestimate Opera Software/Opera Mini, the content preprocessing they do on their proxies is extensive and often surprisingly good.
Found gmaps java app http://boostapps.com/apps/google-maps-2-3-2/ Oh really. Maybe you're right but I seeiously doubt that web based google maps can be loaded at all on the type of phones we're talking about.
OK, just played around with GMaps on OM for a bit. It's pretty much the opposite of what I wrote... I can't get the map itself to load, but I can pick a route, then (after enabling O's "single column mode") it will display directions (with street names etc.) for me. It isn't anyone's idea of great usability, but at least it'll get you where you want to be. Nice find with the GMaps app, I wonder if it still works though - iirc they change the API every so often, which might've broken a few things here and there since 2010, no? But at least Gmail should work just fine using IMAP or POP3 with whatever mail app is on hand.
There is an official Gmail app too. Yandex maps works fine, it comes with maps preloaded. I assume Gmaps does the same. I'm thinking basic street maps which can be stored in text. I'll test the Gmaps later and report back.
The J2ME GMaps still does its job but is a pain in the ass to use. The S60 app works great though. No preloaded maps on either, maybe there is at least a cache of those you already downloaded, dunno. At least for the Midlet that's doubtful though, what with the extremely limited storage space for those things... It even had to go online to download its goddamn TOS/EULA text... OK, but that's enough dicking around with functions I don't even use, which was what lead me to decide to leave the "Smart"phone world for one with better standby time after all. Y'all have fun, I'm going to play some Wolfenstein RPG.
I have Google Maps 2.3.2 on my phone, it doesn't have maps stored on the device. When you move around the map it tells you how much data it's downloading at any given moment. It's pretty slow and somewhat painful, but it does give you maps. I don't really use it though, I know how to get around. An official Gmail app would be handy, I'll keep my eyes out for it. Opera Mini is awesome, you can even watch Youtube videos on it, albeit in low quality.