humm... have you already root your phone? i'll give you the steps:
1. Download Darktremor A2SD from XDA Developers forum.
2. Download SuperOneClick: Follow the install instructions, reboot, then check if you have "SuperUser (SU)" app in drawer. If SU is available, your phone successfully rooted.
3. Download "BusyBox Installer" from market: Install, Open app, if request superuser permission appears, press "ALLOW". then choose busybox version you like, but i suggest you to use stable one like v1.8, newest is 1.9.1 beta. install & reboot.
4. Download "Titanium Backup (TB)" from market: Install, press "ALLOW" for SuperUser permission. now check on TB main screen, look at Overview tab, Root access said "OK" (BusyBox 1. bla bla bla..) then you're ready for next step.
5. Now backup your apps and data from your SD to PC.
6. Download "Mini Tool Partition Wizard" from
www.partitionwizard.co, install then insert your SD card via card reader, don't use the phone.:
- Delete partition
- Create FAT32 - PRIMARY, size depends. for 4GB card you can reserve up to 3GB for data.
- Create EXT2 (not ext3 or 4) - PRIMARY, size 512MB for best, don't max out available space. you still need it for swap.
- Create LinuxSwap - PRIMARY, size: use remaining available space.
- check your settings if all ok then click APPLY.
7. Now copy Darktremor A2SD ZIP file to repartitioned SD card. rename it to "update.zip" also "a2sd_enabler.sh" from xda developer forum.
8. Now put it back to the phone, power on. then download ClockworkMod ROM MANAGER, backup your current ROM. if failed don't worry you can download the originaal from samdroid site.
9. Open Clockworkmod ROM MANAGER, choose Boot Recovery, if failed. Turn off your phone. Press HOME + POWER button to boot into recovery menu. choose wipe data/cache then FLASH update.zip. it'll reboot after finished.
10. Now, download "Terminal Emulator" from market. open it, you'll find the screen like MS-DOS, type "su" for superuser permission.
11. type "a2sd check" to check if a2sd properly installed. don't worry, darktremor is very kind to write down all the information for us. read carefully at each line written.
12. now type in the following commands (try copy-paste each line then hit enter):
To double check everything, reboot your phone and open terminal emulator again, then run the following command, and find a line similar to the highlighted line in the output below:
Output (or use titanium backup to check whether "sdcard (a2sd): XXXMB XXXMB Free" is enabled)
now you're good to go
still confused? try to contact those experts from xda developers. i just followed the steps from majadev
one more thing, use minimal class 4^ sd card. type *#*#7780#*#* after successfully applied a2sd and reset factory setting then install your apps one by one from beginning.