Kto mi to sprawdzi

I often use the Internet. I use Internet as source of information, which helps me by doing my homework. In free moments I write e-mails to my friends and I speak with them on gadu-gadu. In Internet I find information on subject of stars many curiosities, athletes and many different subjects. I often check also weather in Internet.

SPRAWDZI KTOŚ

I use Internet as source of information which helps me TO DO my homework. In free TIME I write e-mails to my friends and I speak with them on gadu-gadu. ON THE Internet I find information ABOUT stars, athletes and many different subjects. I ALSO often check THE weather ON THE Internet

Brakuje jeszcze 2 przedimkow i 1 zaimka, ale to drobiazgi

I often use the internet. I use it (the internet) as a source of information, which helps me in (not by, the internet doesn't do your homework) doing my homework. In (my) free moments (you could also say "When I have free time...." ) I write emails to my friends and talk (not speak) to my friends on gadu-gadu. I find (a lot of) information regarding celebrities (not stars), athletes and many other subjects on the internet. I also, often check the weather on the internet (or....I also check the weather there (on the internet) often....

PS. ...and talk to my friends/and speak to my friends....talk describes 2 way communication while when you speak you do all the talking and your friends listen
you may also wander why I changed the placement of "often" in the last sentence....good article explaining this is available here:http://grammar.ccc.commnet.edu/grammar/adverbs.htm

ooops, you beat me to it mg...sorry lol...