Yes, you can use dwolla to deposit funds on exchanges i.e. Mt gox, Intersango and probably others. But you need to create this DWOLLA account anyway
it looks like the simplest way is online wire ----> exchange ----> BTC
without any additional accounts, this is possible in Europe
for USD it isn't as simple, one extra step, and account is required (and sometimes these requirements are really weird, proving your identity to 3rd parties - and there is a chance that your personal data will leak from 3rd parties some day, during hackers attack) :-(
via SecondLife -- VirWox ---> ...
via LibertyReserve ---> ...
via DWOLLA ---> ...
via Bitinstant ---> CryptoXChange ...chose the weapon
I hope I didn't miss anything - if something is wrong, correct me
what about others? CAD AUD ... South America ... ? and maybe something more for USD ... ?