鬼の居ぬ間に洗濯

When the cats away, the mice will play.

長い物には巻かれろ

You can't fight city hall.

If you can't beat them, join them.

住めば都

Home is where you can make it.

To every bird, his own nest is beautiful.

As they say, home is where you can make it, but/except North Korea.

悪事千里を走る

Bad news travels fast.

早起きは三文の徳

Eary to bed and early to rise makes a man healthy, wealthy and wise. 

塵も積もれば山となる

Many a little makes a mickle.

mickle ミｸﾙ n)たくさん･多量（ｽｺｯﾄﾗﾝﾄﾞ）

英語では沢山の類似表現がある

Save money for a rainy day.  

貯金をしよう雨の日のために（いざという時に備えてお金を貯めておく）

一石二鳥

Killing two birds with one stone. 一石二鳥（なんと日本語と同じ使い方！）

　It's like killing two birds with one stone! それって一石二鳥だね！