一点看法
有两个职位都可以申请的话,个人觉得还是侧重一个好,不过可以稍微提一下自己对另外一个职位的下兴趣和经验
至于邮寄和email,我觉得差别不大,现在倒是有一些公司只接受网上的申请了
email needs no address
in your email, there is no need to attach company address or your own address, becasue it is basically a e-cover letter, however, as you will attach resume and inside which, as you know, you've got to list your address
most companies will print out emails and put them with the letter applications together and then make a short list, so it does not matter if you only send out emails as this is the faster way.
another issue is, if u are interested in two vacancies in one company, better wirte to say you are applying for one and at the same time, you can mention in your cover letter that you are open to other jobs such as blabla (the other one), so that they can judge if you are suit for both or only one etc...