I was sending a mail to all my mail accounts for a test, through php script from localhost. Sometimes It was going to spam filter to my gmail account. And It was going to yahoo account one week later. Why?. I want to go this directly to mail account inbox in quickly.

Probably because you're sending from localhost which can be a spam signal to some email providers

Depends on the mail server your sending to.
If you can, try change from localhost to something different, maybe then it will go through.

I have never had a problem, though. I have had enough luck with it, never a spam email

i try and avoid using the inbuilt mail functions personally, i use the pear mail libraries and the mime librarys, they allow you to set email headers and do full html/text emails. Generaly alot of spam providers will mark up your spam email if your email is missing what they consider vital stuff.

What was your title, sometimes a spam filter places thing in its folder by the title or the content. If you just wrote gibberish for the title, it may have placed it in spam. (Happened to me before)

PHP's default mail function can be a problem sometimes. I use PEAR's mail function.

Thanks for reply!. Now I have used the same mail program from my website. It is going to mail inbox directly. I given my site address as "From: www.mysitename.com" in program. But it was going to mail as www.mysitename.com@go.privatednsserver.com. Why?. I need only the my site name what i want. Should i set anything in my control panel?.