If you want to have access to funds from anywhere, just use an online exchange, or even a bitcoin casino wallet!
If you want to have acces to the same wallet from several places, just import the keys to whatever wallet you want to use on a particular device.
Using online exchange or casino to store your BTC is even more dangerous than a service dedicated to storing Bitcoins. There were alot of cases of exchange and casino owners running away with your BTC compared to dedicated wallet services, although there is still risk.