Hi,
i have full wroking website. I want to make blog for it. I have few questions.
1. Should I make blog on bloghosting website like blogger.com
or host blog myself?
2. Should blog integrate in the website or hosted as subdomain
3. Will blog improve websie rank?

Please, kindly guide me.

No...
Yes....
I believe it can.....

Seriously.....the free blog sites can control you.....deleted for little reason...

Host a blog with a different host...I think it can help with backlinks...
Use a domain name that works with your main site....

Add Wordpress in your website. Do not go for blogger. Wordpress is best and you will get extra traffic on your website using blog.

Blogs work as a base for a website. Selection of good blog can improve you website visibility in search engine rankings. I will suggest you to go for wordpress and blogspot

1. any of the 2 option will do.
2. you it should be.
3. Definitely, it helps your site increase it ranking from having a good quality backlinks from it.

wordpress is a good option than blogger, website with blogs is a good idea..means new contents can be add up

Here are your answers from me...

1. Having own hosted blog is best as blogger often delete blog with out any prior notice.

2. integrating with main site is better here.

3. If you update your blog often with unique posts that really helps in some way.

Much better if you will install wordpress blog into your website. (installing WP blog means your blog will be a sub folder of your website; thus give your a link like this: www.yourdomainname.com/yourblogname

I think you should select the second option, using Wordpress, since it is better for SEO than blogger

wordpress blogger either way

Wordpress is the best choice