For informal emails you could use:

I've attached...

For more formal emails you could write:

Please find attached...

"Please find enclosed" is only used when sending physical items such as letters or parcels, not emails.

For informal emails you could use:

I've attached...

For more formal emails you could write:

Please find attached...

For a discussion of enclosed vs attached please see:

http://www.usingenglish.com/forum/ask-teacher/22264-difference-between-enclosed-attached.html