Islam in depth!

[freundlisch]

Salamo Allahi 3alaikom ajma3in.
first I am a muslim who want to know more about his religion in depth I mean because I believe that I need to learn more about the Islam and the real meaning of some definition like Sohba, Dikr,.. and other stuffs. I feel like my worship is not sincere. this why I want to ask about the meaning of Chahadatan. but I need to understand this meaning in depth not just the definition like to attest that there is only one God and that Muhammed (salla Allaho 3alaihi wa sallam) is his prophet. In adddition, that will help not merely the muslims but also the others believers frok other religions.
Thanks in advance.
salam

[Moadeeb]

Wa alaikom el salam

Check this for a start

http://www.islam-guide.com/

You could also check the islamic library at

http://www.al-mostafa.com/

Hope this helps

Salam

Moadeeb