Boring but common overcards situation - Standard line?

[olavfo]

The flop bet is standard, but then what? On the turn I got two overcards and 4 outs to a straight. I think I tend to bet the turn too often in situations such as this, and that this is a small leak in my play. What's the recommended line in these situations? CO seems tightish with VP$IP 17 over 23 hands.

Party Poker 0.5/1 Hold'em (10 handed) converter

Preflop: Hero is UTG+1 with A[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/diamond.gif[/img].
UTG calls, <font color="#CC3333">Hero raises</font>, <font color="#666666">4 folds</font>, CO calls, Button calls, <font color="#666666">2 folds</font>, UTG calls.

Flop: (9.50 SB) 3[img]/images/graemlins/club.gif[/img], 2[img]/images/graemlins/diamond.gif[/img], T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
UTG checks, <font color="#CC3333">Hero bets</font>, CO calls, Button folds, UTG folds.

Turn: (5.75 BB) 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero ?