"as always" can be translated as 언제나처럼 but it is a bit long. Informally we most commonly say 오늘도 if the event is a daily one as in your example. It is short and clear and informal.
And VERB + -자 form corresponds to "let's (do something), as in 가자, 떠나자, 먹자, etc.
So your sentence can be said as 오늘도 (이제) 아이스크림 먹자. (Using 오늘도 and 이제 together don't seem to work too well though. It's best to pick only one)