I need OneBridge 5.5 to get my work e-mail to go push (Lotus Notes R5). My company say they do not support N73 (only SE 990 and maybe E61). Does any of you know if there is a version of Onebridge 5.5 running for N73 out somewhere?

If the app works on the E61, it is likely to work on the N73, too (if it has been properly written).