While searching for custom ROM, I found below information over internet. I am sharing it with you.
This guide is for s5830i ONLY!!DON'T USE FOR s5830!!It can damage your phone!!
DO NOT TRY FLASHING SOFTWARE FOR OTHER DEVICE!IT WILL BRICK YOUR PHONE!!!READ CAREFUL ALL THE POSTS!!
How to root Galaxy Ace s5830i.
1.Put update.zip in your main directory in the SD card.
2.Turn off your phone.
3.Boot in Recovery by pressing:POWER+VOLUME UP+HOME buttons.
4.In Recovery select Install zip from sd
5.Choose update.zip
6.Reboot your phone and it's ready.There must be a Superuser icon in your Apps menu.
How to unroot
1.Exactly the same just put the file unroot in your main directory and folow the steps.
ClockWorkRecovery
1.Put the file ClockWorkRec5830i.zip in your main directory in SD again.
2.Turn off phone.
3.Boot in Recovery and select apply update.zip
4.Select ClockWorkRec5830i.
5.You have CWR but don't delete ClockWorkRec5830i.zip from the SD because
every time you want to use it you must install it from the SD!!
Flashing s5830i with Odin v1.85
1.Turn off the phone and put it in Download mode by pressing Power+Volume Up+volume down.
2.Open Odin v1.84.Run as Administrator!.
3.Put the files in Odin and don't touch the settings
4.If it's a one-file firmware put it in PDA section.
If it's multiple put the files in the correct section.
5.Click start and don't touch the phone!Don't turn off computer and don't unplug the phone!It will reboot automatically and the first boot will take some time,so don't panic!
If you have "bricked" your s5830i a.k.a stuck at samsung logo just download Odin and flash PDA.tar form the link.
http://www.4shared.com/file/Ls2CAsHv/PDA.html
Everything you're doing is up to you!I'm not responsible if you don't read!There's a binary counter on s5830i so be careful with flashing!
Update:samfirmware.com provide us with odin 1.84 with .pit file for our phone so from now on you can flash firmware from samfirmware.com without problems.
If I helped you,press the thanks button 
This guide is for s5830i ONLY!!DON'T USE FOR s5830!!It can damage your phone!!
DO NOT TRY FLASHING SOFTWARE FOR OTHER DEVICE!IT WILL BRICK YOUR PHONE!!!READ CAREFUL ALL THE POSTS!!
How to root Galaxy Ace s5830i.
1.Put update.zip in your main directory in the SD card.
2.Turn off your phone.
3.Boot in Recovery by pressing:POWER+VOLUME UP+HOME buttons.
4.In Recovery select Install zip from sd
5.Choose update.zip
6.Reboot your phone and it's ready.There must be a Superuser icon in your Apps menu.
How to unroot
1.Exactly the same just put the file unroot in your main directory and folow the steps.
ClockWorkRecovery
1.Put the file ClockWorkRec5830i.zip in your main directory in SD again.
2.Turn off phone.
3.Boot in Recovery and select apply update.zip
4.Select ClockWorkRec5830i.
5.You have CWR but don't delete ClockWorkRec5830i.zip from the SD because
every time you want to use it you must install it from the SD!!
Flashing s5830i with Odin v1.85
1.Turn off the phone and put it in Download mode by pressing Power+Volume Up+volume down.
2.Open Odin v1.84.Run as Administrator!.
3.Put the files in Odin and don't touch the settings
4.If it's a one-file firmware put it in PDA section.
If it's multiple put the files in the correct section.
5.Click start and don't touch the phone!Don't turn off computer and don't unplug the phone!It will reboot automatically and the first boot will take some time,so don't panic!
If you have "bricked" your s5830i a.k.a stuck at samsung logo just download Odin and flash PDA.tar form the link.
http://www.4shared.com/file/Ls2CAsHv/PDA.html
Everything you're doing is up to you!I'm not responsible if you don't read!There's a binary counter on s5830i so be careful with flashing!
Update:samfirmware.com provide us with odin 1.84 with .pit file for our phone so from now on you can flash firmware from samfirmware.com without problems.
If I helped you,press the thanks button
