Right just got it working on my i8510, here are the instructions:
1. Download and install the S60 Platform and Device SDKs for Symbian OS 3rd Edition FP2 v1.1 (
http://www.forum.nokia.com/info/sw.noki ... _SDKs.html) from forum.nokia.com.
2. Download and install the Open C/C++ Plug-in v1.6 (
http://www.forum.nokia.com/info/sw.noki ... ug-In.html) from forum.nokia.com.
3. Navigate to the directory that the SDK has been installed e.g.
C:\S60\devices\S60_3rd_FP2_SDK_v1.1\nokia_plugin.
4. Install the following packages to your phone from the
C:\S60\devices\S60_3rd_FP2_SDK_v1.1\nokia_plugin\openc\s60opencsis directory.
- openc_glib_s60_1_6_SS.sis
- openc_ssl_s60_1_6_SS.sis
- pips_s60_1_6_SS.sis
- stdioserver_s60_1_6_SS.sis
5. Install the following package to your phone from the
C:\S60\devices\S60_3rd_FP2_SDK_v1.1\nokia_plugin\opencpp\s60opencppsis directory.
6. Download the SDL Runtime for S60 3rd edition from
http://koti.mbnet.fi/mertama/sdl.html.
7. Install the SDL Runtime package
SDL-1.2.13-s60-2.3.6_armv5.sisx to your phone.
8. Download the latest version of Dosbox for Symbian S60 (
dosbox_s60_20090623.zip) from
http://sourceforge.net/projects/s60dosbox/files/.
9. Extract the Dosbox zip file downloaded in step 8.
10. Browse to the extracted Dosbox zip file (
dosbox_s60_20090623\full3) and install the
dosbox.sisx package to your phone.
11. Launch Dosbox from the Applications Menu

12. Configure Dosbox how you want it - e.g. Install Windows 3.1/95 (google if you want to know how to do this there are plenty of guides already around).
Best Regards
Dave K.